How To Make Lemon Blueberry Dump Cake At Home

What Is Lemon Blueberry Dump Cake?

Lemon blueberry dump cake is a simple baked dessert where fruit filling and dry cake mix are layered, then topped with butter and baked until bubbly and browned. It eats like a soft fruit cobbler with a crisp, cake-like top, without mixing a batter.

The method relies on moisture from the fruit and melted butter to hydrate the cake mix as it bakes, so the layering matters more than precision stirring.

Why Do Lemon And Blueberry Work So Well Together?

Lemon brightens the flavor and balances sweetness, while blueberries bring body, color, and a gentle tannic edge from the skins. Together they bake into a filling that tastes clear and fresh instead of flat.

If your blueberries are very sweet or very tart, the finished balance will shift. That is normal, and you can adjust sugar and lemon to match the fruit you have.

What Ingredients Do You Need For Lemon Blueberry Dump Cake?

You need fruit, lemon flavor, sugar to taste, a thickener, dry cake mix, and butter. Most versions also include a little salt to keep the flavor from tasting dull.

Here is what each piece does:

• Blueberries provide the filling and moisture that hydrates the cake mix.
• Lemon zest and juice add aroma and acidity, which keeps the fruit tasting bright after baking.
• Sugar rounds the acidity and helps the filling turn glossy.
• Cornstarch (or another starch) thickens the fruit juices so the filling is spoonable, not thin.
• Dry cake mix becomes the tender, crisp-topped layer as it absorbs butter and fruit juices.
• Butter supplies fat, browning, and the hydration pathway for the dry mix.
• Salt sharpens both fruit and “cake” flavor.

Should You Use Fresh Or Frozen Blueberries?

Either works, and the choice mostly affects juiciness and bake time. Fresh blueberries usually bake into a slightly firmer filling, while frozen berries release more liquid and often need a bit more thickener or a few more minutes in the oven.

If using frozen blueberries, do not thaw them first unless you plan to drain and measure the released juices. Baking from frozen helps keep the berries from collapsing too early and turning the filling gray-purple.

Do You Need Pie Filling Or Can You Use Plain Fruit?

You do not need canned pie filling. Plain blueberries plus sugar, lemon, and starch give you more control over sweetness and thickness, and they keep the lemon flavor clean.

Pie filling can work in a pinch, but it varies widely in sweetness, starch level, and lemon flavor. If you use it, reduce added sugar and consider adding fresh lemon zest for aroma.

What Pan Size Works Best For Dump Cake?

A 9-by-13-inch pan is the most forgiving because the layers spread evenly and bake through before the top overbrowns. An 8-by-8 or 9-by-9 pan works, but the dessert will be thicker and may need additional baking time.

If you switch pan size, the main goal is a fully hydrated cake-mix layer with bubbling fruit around the edges.

Practical Pan Guide (Approximate)

Pan Size	Capacity	Layer Thickness	Likely Bake Time
9 x 13 in (23 x 33 cm)	3 qt / 2.8 L	Medium	40–55 min
9 x 9 in (23 x 23 cm)	2 qt / 1.9 L	Thick	50–65 min
8 x 8 in (20 x 20 cm)	1.5 qt / 1.4 L	Thicker	55–70 min

Bake times vary with pan material, oven calibration, fruit temperature, and how evenly the butter is distributed.

Do You Have To “Dump” Everything In, Or Should You Mix?

You should mix the fruit layer, but you should not mix the cake mix into the fruit. Stirring the cake mix into the filling tends to create gummy pockets and prevents the top from crisping.

A clean method is: mix fruit, spread fruit, sprinkle dry mix evenly, then distribute butter so the mix can hydrate and brown.

How Do You Keep Dry Patches From Forming On Top?

Dry patches happen when cake mix does not contact moisture or butter. The fix is simple: spread the dry mix evenly and make sure butter covers as much surface area as possible.

Reliable ways to reduce dry spots:

• Use melted butter and drizzle it slowly across the entire surface.
• If using cold butter, slice it thin and place pieces close together.
• Pat the cake mix gently with a spoon to level it before adding butter.
• Avoid piling the mix in the corners where it can stay dry.

Even with good coverage, a few pale specks can appear. If the top is mostly browned and the fruit is bubbling, it is usually baked through.

What Temperature Should You Bake Lemon Blueberry Dump Cake At?

Bake at 350°F (177°C) for steady thickening and even browning. That temperature gives the filling time to bubble and set before the top becomes too dark.

If your oven runs hot or you use a dark metal pan, you may need to tent loosely with foil near the end to prevent overbrowning.

Lemon Blueberry Dump Cake Recipe (U.S. And Metric)

What Equipment Do You Need?

You need a baking pan, a bowl for the fruit, a spoon or spatula, and a way to distribute butter. A microplane or fine grater helps for zest, but it is optional.

Common options:

• 9 x 13-inch (23 x 33 cm) baking dish, glass or metal
• Mixing bowl
• Zester or fine grater (optional)
• Citrus juicer (optional)
• Measuring cups and spoons or a kitchen scale

What Ingredients Do You Need?

This recipe aims for a bright lemon note, a thick spoonable filling, and a well-browned top.

Fruit Layer

• Blueberries: 6 cups (about 900 g) fresh or frozen
• Granulated sugar: 1/2 cup (100 g), plus more to taste
• Cornstarch: 2 tablespoons (16 g)
• Fine salt: 1/4 teaspoon
• Lemon zest: 2 teaspoons (from 1–2 lemons)
• Lemon juice: 3 tablespoons (45 ml)

Top Layer

• Dry yellow cake mix: 1 box, about 15–16 oz (about 425–450 g)
• Unsalted butter, melted: 10 tablespoons (140 g)
  • If using salted butter, reduce added salt slightly.

Optional, For Texture

• Chopped nuts: 1/2 cup (60–70 g)
  Use only if you want a more brittle top. Leave them out for a smoother crust.

What Are The Step-By-Step Instructions?

These steps are written to prevent dry cake mix and to keep the filling from turning watery.

1. Heat the oven. Set to 350°F (177°C). Place a rack in the middle.
2. Prepare the pan. Lightly grease the baking dish, especially the corners.
3. Mix the fruit layer. In a bowl, combine blueberries, sugar, cornstarch, salt, lemon zest, and lemon juice. Stir until the cornstarch disappears into the juices.
4. Spread the fruit. Scrape the mixture into the pan and spread it into an even layer.
5. Add the dry mix. Sprinkle the dry cake mix evenly over the fruit. Level it gently with the back of a spoon. Do not press hard.
6. Add butter evenly. Drizzle melted butter slowly over the entire surface, aiming for full coverage. If using nuts, sprinkle them on after the butter so they adhere.
7. Bake. Bake until the fruit bubbles at the edges and the top is mostly golden brown, 40–55 minutes for a 9 x 13-inch pan. Thicker pans or frozen fruit may push you toward the longer end.
8. Cool before serving. Let the dessert cool 20–30 minutes so the filling thickens. It will still be warm, but less runny.

How Do You Know When It Is Done?

It is done when the fruit is actively bubbling and the top is browned in most spots. Bubbling matters because it tells you the starch has reached a temperature where it can thicken properly.

If the top browns early but the fruit is not bubbling, tent loosely with foil and continue baking until bubbling appears.

Can You Make It More Or Less Lemon-Forward?

Yes, and the most effective change is zest. Lemon zest carries the aromatic oils that read as “lemon flavor” even after baking.

Simple adjustments:

• For more lemon, add 1–2 more teaspoons zest.
• For more tartness, add 1 more tablespoon (15 ml) lemon juice, and consider an extra teaspoon sugar to keep balance.
• For less lemon, reduce zest to 1 teaspoon and keep the juice, since a little acidity helps the filling set and taste clean.

Can You Reduce Sugar Without Ruining The Texture?

You can reduce sugar, but go slowly because sugar affects not only sweetness, but also how glossy and thick the filling feels. Less sugar can make the fruit taste sharper and the filling seem looser.

A practical approach is to reduce by 2 tablespoons (25 g) at a time, especially if your berries are naturally sweet.

What Are The Best Serving Temperatures And Textures?

It serves best warm after a short cooling period, when the top is crisp and the filling is thick enough to spoon cleanly. If served piping hot, the filling can be thin because starch thickens more as it cools.

Chilled leftovers are firmer and slice more neatly, but the top will soften as it sits.

Should You Add Any Toppings?

Toppings are optional. If you add one, keep it simple so the lemon and blueberry stay in front.

Common choices:

• A scoop of vanilla ice cream
• Unsweetened whipped cream
• A spoonful of plain yogurt if you want tang

If you serve with something cold, the cake layer stays crisper longer.

Can You Make Lemon Blueberry Dump Cake Ahead Of Time?

Yes, but it is best baked close to serving if you want a crisp top. The cake layer softens as it absorbs moisture from the filling.

If you need to prep ahead, you can mix the fruit layer and keep it refrigerated for several hours, then assemble and bake. If the fruit is cold going into the oven, plan for a longer bake.

How Should You Store Leftovers Safely?

Store leftovers covered in the refrigerator within 2 hours of baking. Fruit desserts are moist and should be treated as perishable once cooled.

For best quality, refrigerate in the baking dish or transfer to a shallow airtight container to cool faster before sealing.

How Long Does Lemon Blueberry Dump Cake Last In The Fridge?

For food safety, plan to eat refrigerated leftovers within 3–4 days. Quality is best in the first two days, when the flavors are bright and the top is not fully softened. [1][2]

If anything smells off, shows visible mold, or tastes fermented, discard it.

Can You Freeze Lemon Blueberry Dump Cake?

Yes, but freezing softens the top. Freeze for convenience, not for peak texture.

A careful method:

1. Cool completely.
2. Portion into airtight containers or wrap tightly.
3. Freeze up to 2–3 months for best quality.
4. Thaw overnight in the refrigerator.

Reheat to restore some surface crispness, but do not expect the same crackly top as day one.

What Is The Best Way To Reheat It Without Drying It Out?

Reheat gently so the fruit warms through before the top scorches. Ovens vary, so watch closely.

Options:

• Oven: 300–325°F (150–163°C), covered loosely with foil, until warm.
• Microwave: short bursts at medium power. This warms quickly but softens the top.

If you want a slightly crisper surface after microwaving, a brief oven warm-up can help, but it is optional.

What Common Problems Happen, And How Do You Fix Them?

Most issues come from uneven butter coverage, watery fruit, or underbaking.

The top is powdery in places.
The cake mix did not hydrate. Next time, level the mix and distribute butter more evenly. If you see dry spots halfway through baking, you can drizzle a little more melted butter over those areas.

The filling is thin.
The dessert may be underbaked, or the fruit released more liquid than expected. Bake until bubbling is active. If using frozen berries, consider increasing cornstarch by 1 tablespoon (8 g).

The top is too brown but the fruit is not bubbling.
Tent with foil and continue baking until bubbling appears.

The cake layer is gummy.
This often happens when the dry mix is stirred into the fruit, or when too much liquid sits on top. Keep layers distinct and avoid adding extra liquid unless you have a specific reason.

What Simple Variations Still Count As Lemon Blueberry Dump Cake?

You can keep the same method and shift the flavor or texture without changing the basic idea.

Straightforward variations:

• Add a second berry (like raspberries) for sharper acidity, but expect more juice.
• Swap the thickener to tapioca starch or arrowroot if you prefer, though results vary slightly.
• Add spice lightly, such as a small pinch of ground ginger, if you want warmth behind the lemon.
• Use a different citrus like lime, but keep the zest since it carries the aroma.

If you change fruit types, you may need to adjust sugar and starch because different fruits release different amounts of water.

Endnotes

[1] usda.gov
[2] foodsafety.gov