Spaghetti Squash with Simple Red Sauce (Healthy, Satisfying, Weeknight-Ready)

Spaghetti squash makes an easy, low-carb stand-in for pasta. The strands are tender with a mild sweetness that welcomes bright tomato sauce and a salty finish of Parmesan. You get the familiar comfort of a bowl of noodles without the weight, and you can make it with basic equipment you already own.

The method is straightforward. Cook the squash until it pulls into long strands. Build a simple stovetop red sauce while the squash softens. Toss them together, finish with cheese, and serve. The result is clean, balanced, and filling. It works in any season and fits a wide range of diets.

This version leans on pantry staples and a few fresh ingredients. There are no complicated steps. You can keep it strictly microwave and stovetop, or you can roast the squash in the oven if you prefer deeper flavor. Either way, the dish stays economical and practical for busy evenings.

Why this recipe works

Spaghetti squash contains more water than wheat pasta, so it needs an approach that keeps the strands distinct. Salting lightly and letting steam escape during cooking prevents sogginess. The sauce simmers long enough to thicken and cling to the squash without drowning it. A measured amount of fat keeps the texture silky while letting the fresh tomato flavor lead.

The sauce uses crushed tomatoes or passata as a primary base for consistent results. Onion and garlic build savoriness, tomato paste adds body, and dried oregano and basil provide a classic profile. A small pinch of sugar is optional and balances acidity if your tomatoes taste sharp. The Parmesan at the end gives salt and umami without requiring heavy amounts of oil.

What you’ll need

Required equipment

• Large microwave-safe plate or shallow dish
• Sharp chef’s knife
• Sturdy cutting board
• Spoon for seed removal
• Microwave-safe plastic wrap or a damp paper towel
• Large nonstick or stainless skillet, 11 to 12 inches
• Wooden spoon or heatproof spatula
• Large mixing bowl
• Measuring cups and spoons
• Fine grater for Parmesan
• Optional: sheet pan and parchment if roasting instead of microwaving

Prep and cook times

• Active prep time: 15 minutes
• Cook time: 40 to 50 minutes (microwave method is fastest; roasting takes longer)
• Total time: 55 to 65 minutes
• Servings: 6 as a light main or hearty side

Yield

From a 5 pound squash you can expect about 7 to 8 cups of strands, enough to satisfy six modest portions or four larger ones. The sauce quantity below is scaled to coat the strands without pooling.

Ingredients (US and Metric)

For the spaghetti squash

• 1 large spaghetti squash, about 5 pounds (about 2.3 kg)
• 1 tablespoon olive oil (15 mL)
• ½ teaspoon fine sea salt (3 g)

For the red sauce

• 1 tablespoon olive oil (15 mL)
• 1 medium yellow onion, diced small (about 1 cup; 150 g)
• 3 garlic cloves, minced (about 1 tablespoon; 9 g)
• 2 tablespoons tomato paste (30 g)
• 3 cups crushed tomatoes or passata (24 ounces; 680 g)
• 1 teaspoon dried oregano (1 g)
• ½ teaspoon dried basil (0.5 g) or 1 tablespoon chopped fresh basil (4 g)
• ½ to ¾ teaspoon fine sea salt, to taste (3 to 4 g)
• ¼ teaspoon black pepper (1 g)
• Pinch of sugar, optional, only if needed to balance acidity
• ½ cup freshly grated Parmesan, for serving (about 1.8 ounces; 50 g)
• Extra basil or parsley for garnish, optional

Notes on accuracy and substitutions

• Crushed tomatoes and passata vary in acidity and thickness. If your sauce tastes sour, add the optional pinch of sugar and simmer a few extra minutes. If it seems thin, simmer uncovered to reduce.
• If you prefer oil control, reduce the oil in the sauce to 2 teaspoons and add a splash of water as the onions cook to prevent sticking.
• Parmesan adds sodium and richness. If you need a lower-sodium finish, reduce the added salt and finish with lemon zest or chopped herbs instead.

Step-by-step instructions

1) Safely split and prep the squash

1. Set the squash on a towel-lined cutting board so it does not slip. Trim a very thin slice from one end to create a flat base if needed.
2. Using a sharp chef’s knife, cut the squash in half lengthwise. If the shell is very hard, microwave the whole squash for 2 to 3 minutes first to soften the rind.
3. Scoop out the seeds and stringy center with a spoon.
4. Rub the cut sides with 1 tablespoon olive oil and sprinkle evenly with ½ teaspoon salt.

2) Cook the squash: microwave or roast

Microwave method (fastest, lightest texture):

1. Place both halves cut side down on a large microwave-safe plate. Cover with microwave-safe plastic wrap or a damp paper towel, leaving a small vent for steam.
2. Microwave on high for 8 to 10 minutes. The exact time depends on your microwave and squash size. Start checking at 8 minutes.
3. Flip the halves cut side up and rest for 5 minutes to let steam escape.
4. Test doneness by pulling a fork across the flesh. It should separate into long strands that are tender yet springy. If still firm, microwave in 1 to 2 minute increments until done.

Oven roasting method (deeper flavor, drier strands):

1. Heat the oven to 400°F (200°C). Line a sheet pan with parchment.
2. Place the oiled, salted halves cut side down.
3. Roast for 35 to 45 minutes until the skin yields to pressure and the strands pull easily with a fork.
4. Turn cut side up and cool 5 to 10 minutes, which helps the strands set and stay distinct.

When the halves are cool enough to handle, hold a piece in a towel and scrape the flesh with a fork into a large bowl. Fluff gently to separate the strands.

3) Make the red sauce while the squash cooks

1. Warm 1 tablespoon olive oil in a large skillet over medium heat.
2. Add the diced onion with a small pinch of salt. Cook, stirring often, until translucent and lightly golden at the edges, about 8 to 10 minutes. If the pan looks dry, add a tablespoon of water to keep the onions soft.
3. Stir in the minced garlic and cook 30 seconds until fragrant.
4. Add the tomato paste and cook 1 minute, stirring to coat the onions. This step caramelizes the paste and builds depth.
5. Pour in the crushed tomatoes or passata. Add oregano, basil, ½ teaspoon salt, and black pepper.
6. Bring to a gentle simmer. Reduce heat to low. Simmer 15 to 20 minutes, uncovered, stirring occasionally. The sauce should thicken and reduce slightly so it clings to the squash. Taste and adjust with a pinch of sugar only if the acidity is sharp. Add more salt if needed.

4) Combine and finish

1. Add the squash strands to the skillet if it is large enough, or pour the sauce over the strands in the mixing bowl.
2. Toss gently with tongs or a wide spoon until the strands are evenly coated.
3. Plate in warm bowls. Top each portion with a generous spoon of freshly grated Parmesan. Add a few basil or parsley leaves if you like.

How to avoid watery strands

Spaghetti squash holds moisture. These steps keep the texture pleasantly al dente.

• Vent the cover when microwaving so steam escapes.
• After cooking, rest the halves cut side up for 5 to 10 minutes before scraping.
• If the strands seem wet, spread them in the empty skillet over medium heat for 1 to 2 minutes, tossing until excess moisture evaporates. Do not brown.

Flavor variations and add-ins

This base recipe takes well to additions. Keep total sauce volume proportional to the squash so strands remain distinct.

Protein options

• Ground turkey or chicken: Brown 12 ounces to 1 pound (340 to 454 g) in 1 teaspoon oil. Season lightly with salt and pepper. Set aside and fold into the finished sauce.
• Italian sausage: Remove 12 ounces (340 g) from casings and brown. Drain excess fat.
• Lentils: Simmer 1 cup cooked lentils (200 g) into the sauce for more fiber and protein.
• Meatballs: Add bite-size meatballs to the sauce during the last 10 minutes to warm through.

Vegetable boosters

• Mushrooms: Sauté 8 ounces (225 g) sliced mushrooms in 1 teaspoon oil until browned. Add to the sauce.
• Zucchini or bell pepper: Dice 1 medium zucchini or pepper and soften with the onions.
• Spinach or kale: Stir 3 cups baby spinach (90 g) or 2 cups chopped kale (70 g) into the hot sauce until wilted.
• Olives and capers: Add ¼ cup sliced olives (35 g) and 1 tablespoon capers (9 g) for a puttanesca-style twist.

Seasoning shifts

• Red pepper flakes: ¼ teaspoon for gentle heat.
• Fresh herbs: Finish with 1 to 2 tablespoons chopped parsley or basil.
• Creamy finish: Stir 3 tablespoons ricotta (45 g) or 2 tablespoons heavy cream (30 mL) into the sauce for a softer profile.
• Dairy-free: Skip Parmesan and finish with a dusting of nutritional yeast to taste.

Make-ahead, storage, and reheating

• Make-ahead: The sauce keeps well. Cook it up to 4 days in advance and refrigerate in a sealed container. Reheat gently before tossing with freshly cooked strands.
• Refrigerator: Store combined leftovers in an airtight container for up to 4 days.
• Reheating: Microwave individual portions for 1 to 2 minutes, stirring halfway, or warm on the stovetop over low heat with a splash of water if needed.
• Freezer: Freeze the red sauce on its own for up to 3 months. Spaghetti squash strands do not freeze well; they tend to weep water upon thawing and lose texture.

Ingredient sourcing and picking a good squash

Choose a firm, heavy squash with matte skin and no soft spots. A dry, corky stem indicates proper curing. Size affects strand thickness and moisture. Large squash produce longer strands and slightly more water. Medium to large, in the 4 to 5 pound range, is a good balance for texture and yield. Store whole squash in a cool, dry place for several weeks. Once cut, wrap and refrigerate and cook within two days.

Nutrition information

The estimates below are based on the ingredient quantities in this recipe, divided into six servings.

• Calories: about 170 kcal
• Protein: about 6 g
• Total fat: about 7 g
• Saturated fat: about 2.5 g
• Carbohydrates: about 24 g
• Fiber: about 4 to 5 g
• Total sugars: about 8 g
• Sodium: about 400 to 450 mg

Actual values will vary with tomato brand, salt level, cheese amount, and the water content of your squash.

Common questions

Can I cook the squash whole?
You can microwave a whole squash for 3 to 5 minutes to soften the rind for safer cutting. Cooking it completely whole traps more moisture and can lead to mushy strands, so splitting first gives better texture.

Is there a way to get longer, more noodle-like strands?
Cut the squash crosswise into rings rather than lengthwise, scrape out seeds from each ring, and roast the rings. The fibers run around the circumference, so rings preserve strand length. For this recipe, lengthwise halves are simpler and faster, but rings are an option when you want extra long strands.

Can I replace crushed tomatoes with fresh?
Yes. Use 3 to 3½ cups peeled, chopped ripe tomatoes (600 to 700 g). Simmer longer to reduce the added liquid and concentrate flavor.

What if my sauce is too tart?
Simmer 3 to 5 minutes more to drive off sharp acidity. Add a pinch of sugar only if needed. A teaspoon of butter whisked in at the end can also round the edges.

How do I make this without cheese?
Skip the Parmesan and finish with chopped herbs and a drizzle of good olive oil. Nutritional yeast works as a savory topper if you want a cheese-like note.

Can I use jarred sauce?
You can. Warm 3 cups (680 g) of your preferred sauce and proceed. The homemade version here gives fresher flavor and a cleaner label, but jarred sauce is convenient.

Troubleshooting and fixes

Strands are wet or clumping

• Spread cooked strands in a dry skillet over medium heat and toss for 1 to 2 minutes to evaporate excess moisture.
• Use a sauce that is thick enough to cling. Reduce your sauce longer if it looks thin.

Squash tastes bland

• Season the strands lightly with salt before tossing with the sauce.
• Finish with an extra sprinkle of Parmesan, a turn of black pepper, and a few chopped herbs to lift aroma.

Onions browning too quickly

• Lower the heat and add a tablespoon of water. Gentle sweating keeps the sauce sweet, not burnt.

Sauce is too thick

• Thin with 2 to 3 tablespoons of water and simmer 1 minute to bring it back together.

Sauce is too thin

• Simmer uncovered until a spoon dragged across the pan leaves a line that closes slowly. The texture should be glossy and just coat the spoon.

Scaling the recipe

For 2 to 3 servings

• Use a 2½ to 3 pound squash.
• Halve the sauce ingredients.
• Keep the simmer time similar; smaller volumes thicken faster, so watch closely.

For 8 to 10 servings

• Roast two medium squash on a full sheet pan.
• Double the sauce in a wide Dutch oven or two skillets to maintain fast reduction.
• Hold the cooked strands uncovered for a few minutes before combining to release steam.

Food safety and handling

Cool leftovers quickly by spreading in a shallow container before refrigerating. Reheat to steaming hot throughout. If you add meat, cook it to a safe internal temperature before combining with the sauce. Use clean utensils when portioning to avoid contamination, especially if serving family-style.

Serving suggestions

• As a light main with a simple green salad dressed with olive oil and vinegar.
• With roasted vegetables on the side for a full produce-forward plate.
• Topped with sliced grilled chicken or shrimp when you want more protein.
• As a base for eggs. A soft-cooked egg on top turns it into a hearty brunch.

The recipe

Spaghetti Squash with Simple Red Sauce

Equipment
Large microwave-safe plate, chef’s knife, cutting board, spoon, microwave-safe wrap or damp paper towel, large skillet, wooden spoon, large bowl, grater, measuring tools. Sheet pan and parchment if roasting.

Prep time 15 minutes
Cook time 40 to 50 minutes
Total time 55 to 65 minutes
Servings 6

Ingredients
Squash

• 1 spaghetti squash, about 5 lb (about 2.3 kg)
• 1 tbsp olive oil (15 mL)
• ½ tsp fine sea salt (3 g)

Red Sauce

• 1 tbsp olive oil (15 mL)
• 1 medium yellow onion, diced small, about 1 cup (150 g)
• 3 garlic cloves, minced, about 1 tbsp (9 g)
• 2 tbsp tomato paste (30 g)
• 3 cups crushed tomatoes or passata (24 oz; 680 g)
• 1 tsp dried oregano (1 g)
• ½ tsp dried basil (0.5 g) or 1 tbsp fresh chopped basil (4 g)
• ½ to ¾ tsp fine sea salt, to taste (3 to 4 g)
• ¼ tsp black pepper (1 g)
• Pinch of sugar, optional
• ½ cup finely grated Parmesan, for serving (50 g)
• Fresh basil or parsley, optional

Instructions

1. Prep the squash. Halve lengthwise, scoop seeds, rub cut sides with 1 tbsp oil, season with ½ tsp salt.
2. Cook the squash.
   Microwave: Place halves cut side down on a microwave-safe plate. Cover with vented wrap. Microwave on high 8 to 10 minutes until a fork pulls long strands. Rest cut side up 5 minutes.
   Oven: Heat to 400°F (200°C). Place halves cut side down on a parchment-lined pan. Roast 35 to 45 minutes until tender. Rest 5 to 10 minutes.
   Scrape strands into a bowl and fluff.
3. Make the sauce. Warm 1 tbsp oil in a large skillet over medium heat. Cook onion with a pinch of salt until translucent and lightly golden, 8 to 10 minutes. Stir in garlic for 30 seconds. Stir in tomato paste for 1 minute. Add crushed tomatoes, oregano, basil, ½ tsp salt, and pepper. Simmer gently, uncovered, 15 to 20 minutes, stirring occasionally, until thickened and glossy. Adjust salt. Add a pinch of sugar only if needed.
4. Combine and serve. Toss squash strands with enough sauce to coat. Portion into bowls. Top with Parmesan and herbs.

Per-serving nutrition (approximate, 1 of 6)
170 kcal; 6 g protein; 7 g fat; 2.5 g saturated fat; 24 g carbohydrates; 4 to 5 g fiber; about 400 to 450 mg sodium.

Tips for success

• Cook the squash until just tender. Overcooking breaks the fibers and turns strands mushy.
• Let steam escape before scraping. This brief rest keeps strands springy.
• Reduce the sauce enough to cling. You want light body, not soupiness.
• Taste and correct salt at the end. Tomatoes vary. Parmesan adds salt, so season a little under and adjust after adding cheese.

Optional upgrades for different goals

Higher protein
Stir in a pound of browned turkey or add 1½ cups cooked lentils. Adjust salt after adding.

More vegetables
Fold in sautéed mushrooms, a diced zucchini, or a handful of chopped kale. Add sturdy vegetables with the onions and quick-wilting greens near the end.

Gentle heat
Add ¼ teaspoon crushed red pepper with the garlic. For bigger heat, add ½ teaspoon.

Creamy style
Stir in 2 tablespoons heavy cream or ricotta right before serving. This softens acidity without muting tomato flavor.

Dairy-free finish
Skip the cheese and drizzle with a teaspoon of olive oil per bowl. Add herbs for aroma.

Cleanup and storage planning

Cook the sauce in a wide skillet so it reduces efficiently and you can toss the strands directly in the pan. If you plan for leftovers, store the sauce and strands separately so the texture stays firm for a second meal. Keep both in tight containers and cool promptly. For day-two service, rewarm the sauce to a gentle simmer before combining with freshly warmed strands.

Closing

This dish delivers the comfort of tomato-tossed noodles with the lighter feel of vegetables at the center of the plate. The method is simple, repeatable, and flexible. Keep it as written for a clean, weeknight meal, or use it as a base for protein and seasonal vegetables. Either way, you get a bowl that tastes balanced and satisfying without a lot of fuss.