Dump and Bake Kielbasa and Pierogi Casserole With Onions and Cheddar Cheese

What Is Dump And Bake Kielbasa And Pierogi Casserole?

It is a one-dish bake where pierogi, sliced kielbasa, onions, and a simple creamy sauce cook together in the oven. “Dump and bake” means you combine the ingredients in the baking dish without pre-cooking, then bake until hot and bubbling.

Why Do The Onions Turn Tender Without Sautéing?

Thinly sliced onions soften because they steam under the foil while the casserole bakes. They will taste milder and sweeter than raw once fully tender.

What Ingredients Do You Need?

You need pierogi, kielbasa, onions, cheddar cheese, and enough liquid to keep the pierogi from drying out while they bake.

A good basic list:

• Pierogi (frozen or thawed)
• Kielbasa (typically a smoked sausage)
• Onion
• Cheddar cheese
• Sour cream (for creaminess) plus milk and broth (for moisture)
• Simple seasonings

Do You Have To Thaw The Pierogi First?

No, you do not have to thaw them, but frozen pierogi usually need a little more time and a touch more liquid. Thawed pierogi bake faster and tend to absorb sauce more evenly.

Pierogi Starting State	Covered Bake Time (At 375°F / 190°C)	Liquid Adjustment
Thawed	30–35 minutes	Use recipe as written
Frozen	40–50 minutes	Add 60 ml (1/4 cup) broth or milk

What Baking Dish And Equipment Work Best?

A 23-by-33 cm (9-by-13-inch) baking dish works well because the casserole spreads out and heats evenly. If you use a smaller, deeper dish, plan on a longer covered bake so the center gets fully hot.

You will also need a mixing bowl, a whisk or fork, and foil.

How Do You Make Dump And Bake Kielbasa And Pierogi Casserole?

You combine the sauce, pierogi, kielbasa, onions, and part of the cheese in the dish, cover, and bake until the onions are tender and the sauce is bubbling. Then you uncover, add the remaining cheddar, and bake briefly to melt and lightly brown the top.

Dump And Bake Kielbasa And Pierogi Casserole With Onions And Cheddar Cheese Recipe

This recipe is written for fully cooked kielbasa, which is common for smoked sausage. If your sausage is not fully cooked, see the safety note in the “When Is It Done?” section.

Yield And Timing

• Servings: 6 (about 1 1/2 cups per serving)
• Prep time: 10–15 minutes
• Bake time: 45–65 minutes, depending on whether the pierogi are frozen
• Rest time: 10 minutes

Ingredients (U.S. And Metric)

• Cooking spray or butter for the dish
• 1 large yellow onion, thinly sliced (about 10 oz / 280 g)
• 1 lb pierogi, frozen or thawed (16 oz / 450 g)
• 12 to 14 oz kielbasa, sliced into 1/4-inch rounds (340 to 400 g)
• 3/4 cup sour cream (180 g)
• 1/2 cup milk (120 ml)
• 1/2 cup chicken broth or water (120 ml)
• 1 tbsp melted butter (14 g), optional but helpful for richness
• 1 tsp sweet paprika (2 g), optional
• 1 tsp garlic powder (3 g)
• 1/2 tsp black pepper (1 g)
• 1/4 tsp salt (1.5 g), optional and to taste
• 6 oz cheddar cheese, shredded, divided (170 g)
• 2 tbsp chopped chives or sliced green onions (optional, for serving)

Instructions

1. Heat the oven to 375°F (190°C). Grease a 9-by-13-inch (23-by-33 cm) baking dish.
2. In a bowl, whisk the sour cream, milk, broth, and melted butter (if using) until smooth. Whisk in paprika, garlic powder, pepper, and salt.
3. Add the sliced onion to the baking dish. Scatter the pierogi and sliced kielbasa over the onions.
4. Pour the sauce over everything. Add about half the cheddar (3 oz / 85 g). Toss gently in the dish to coat as evenly as you can.
5. Cover tightly with foil. Bake until the onions are tender and the sauce is bubbling at the edges:
   • Thawed pierogi: 30–35 minutes
   • Frozen pierogi: 40–50 minutes (add an extra 1/4 cup / 60 ml liquid if needed; see table above)
6. Uncover. Sprinkle the remaining cheddar over the top. Bake uncovered for 10–15 minutes, until the cheese melts and the casserole is bubbling.
7. Rest for 10 minutes before serving so the sauce thickens slightly. Top with chives or sliced green onions, if using.

When Is It Done?

It is done when the pierogi are hot throughout, the onions are fully tender, and the sauce is steadily bubbling around the edges and through the center. If the center is not bubbling, keep baking covered for 5–10 minutes and check again.

Kielbasa is often sold fully cooked, but not always. Check the package wording. If it is not fully cooked, it must reach 160°F (71°C) in the thickest pieces, and you may prefer to brown it in a skillet first to avoid overbaking the pierogi.

How Do You Keep The Casserole From Drying Out?

Keep it covered for most of the bake and use enough liquid in the sauce. If your oven runs hot, your dish is wide and shallow, or your pierogi are very dry from freezer burn, you may need an extra splash of broth or milk (up to 1/4 cup / 60 ml).

Can You Make It Ahead?

Yes, but the texture is best baked soon after assembling. You can slice the onion and kielbasa and shred the cheese up to 2 days ahead, then mix the sauce and assemble just before baking.

If you want to assemble the full casserole ahead, do it no more than 12 hours in advance, cover, and refrigerate. Add 5–15 minutes to the covered bake time because the dish starts cold.

What Simple Variations Work Without Changing The Method?

These changes usually work without altering the basic steps:

• Add 2 cups (about 60 g) baby spinach on top during the last 10 minutes, just to wilt.
• Swap cheddar for another good-melting cheese, keeping the same weight.
• Add 1/2 tsp (1 g) crushed red pepper for heat, if you like it.
• Use two smaller onions instead of one large if that is what you have.

How Should You Store And Reheat Leftovers Safely?

Cool leftovers promptly and refrigerate within 2 hours of baking. Store covered in the refrigerator for up to 3 to 4 days.

Reheat until steaming hot throughout:

• Oven: Cover and warm at 350°F (175°C) until hot, usually 20–30 minutes depending on thickness.
• Microwave: Reheat in short intervals, stirring once if you can, until hot all the way through.

If the sauce looks tight after chilling, add a small splash of milk or broth before reheating. Do not leave dairy-based leftovers at room temperature to “soften” for long; use gentle heat instead.