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Blueberry dump cake in a white bowl with a scoop of vanilla ice cream and powdered sugar on white marble
Luna Hossain

Blueberry Dump Cake Recipe

A jammy lemon-blueberry filling topped with a pebbled golden cake mix crust — assembled in 10 minutes with no mixing, no batter, and no special equipment.
Calories: ~248 kcal | Fat: ~7g | Carbohydrates: ~100g | Sugar: ~34g | Protein: ~6g | Sodium: ~268mg
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Prep Time 10 minutes
Cook Time 50 minutes
Total Time 1 hour
Servings: 12
Course: Easy Cakes
Cuisine: American
Calories: 248
Ingredients Equipment Method Notes

Ingredients
  

  • For the Blueberry Filling:
  • - 5 cups 600g fresh blueberries, rinsed and thoroughly dried
  • - 3 tablespoons 38g granulated white sugar
  • - 1 tablespoon 8g cornstarch (also called cornflour outside the US)
  • - 2 tablespoons 30ml fresh lemon juice
  • - 1 teaspoon finely grated lemon zest zest only no white pith
  • - ¼ teaspoon fine sea salt
  • For the Topping:
  • - 1 box 15.25 oz / 432g yellow cake mix, dry and unmixed
  • - ½ cup 113g cold unsalted butter, sliced into ¼-inch rounds
  • For Garnish and Serving:
  • - 1 teaspoon finely grated lemon zest zest only no white pith
  • - 2 thin lemon rounds sliced from 1 fresh lemon
  • - ¼ cup 30g fresh blueberries
  • - Vanilla ice cream for serving

Equipment

  • Required:
  • 9×13 inch (23×33cm) ceramic or glass baking dish
  • Large mixing bowl — for tossing the blueberry filling
  • Silicone spatula or large spoon — for spreading and tossing
  • Microplane or fine box grater — for lemon zest
  • Citrus juicer or fork — for lemon juice
  • Kitchen scale (strongly recommended — gram weights are more reliable than volume for blueberries and butter)
  • Sharp knife and cutting board — for slicing the butter into rounds
  • Wire cooling rack — for resting the dish after baking
  • Serving spoon or large slotted spoon — the filling is fluid when hot and needs a deep spoon
  • Optional:
  • Oven thermometer — recommended if your oven has a history of running hot or cold
  • Small fine mesh sieve — for an optional powdered sugar dusting at serving

Method
 

  1. Position oven rack in the middle slot and preheat to 350°F (175°C). Lightly grease a 9×13 inch (23×33cm) ceramic or glass baking dish with butter or non-stick spray and set aside.
  2. In a large mixing bowl, combine the blueberries, granulated sugar, cornstarch, lemon juice, lemon zest, and salt. Fold with a silicone spatula for 15 to 20 strokes until every berry is evenly coated and no dry cornstarch remains at the bottom of the bowl.
  3. Pour the blueberry filling into the prepared dish and spread into an even layer edge to edge.
  4. Pour the dry yellow cake mix evenly over the blueberry filling and spread with a spatula until the fruit is completely covered with no exposed gaps.
  5. Slice the cold butter into ¼-inch (6mm) rounds and arrange them across the surface of the dry cake mix in an even grid pattern — do not stir or press the layers together at any point.
  6. Bake at 350°F (175°C) for 45 to 50 minutes, beginning to check at 40 minutes, until the topping peaks are deep golden-amber, the blueberry filling is visibly bubbling through the topping in at least two spots, and the edges show a slight pull-away from the dish sides.
  7. Remove from the oven and place on a wire cooling rack. Rest for 15 minutes before garnishing.
  8. Scatter 1 teaspoon lemon zest evenly over the surface of the warm cake, place 2 thin lemon rounds in the center, and scatter ¼ cup fresh blueberries across the topping. Serve immediately with a generous scoop of vanilla ice cream per bowl.

Notes

- Butter: must be cold from the fridge — melted or softened butter produces a flat, dense topping without the pebbled texture.
- Frozen blueberries: use directly from frozen, do not thaw — increase cornstarch to 1½ tablespoons (12g) to account for extra juice release.
- Lemon juice: fresh only — bottled juice lacks the acidity and aromatics needed to brighten the filling.
- Cake mix: use dry and unmixed — do not add eggs, oil, or water to the box.
- Pan material: ceramic or glass only — dark metal pans overbrown the topping before the filling bubbles through.
- Storage: cover loosely with foil at room temperature up to 2 days, or refrigerate up to 4 days. Do not wrap tightly — trapped steam softens the topping.
- Freeze baked: portion individually, wrap tightly, freeze up to 2 months — thaw overnight in fridge, reheat at 325°F (165°C) for 12 to 15 minutes.
- Make ahead: prepare and refrigerate the blueberry filling up to 24 hours ahead — assemble and bake just before serving.
- Scaling: halve into 8×8 dish, 35–40 min. Double into two separate 9×13 dishes. Cake mix leavening does not scale linearly — do not combine into one larger vessel.
- Altitude: above 3,500 feet, extend bake time 8 to 12 minutes beyond first visible bubbling to ensure cornstarch fully gelatinizes.
- Allergens: contains gluten (cake mix), dairy (butter). Check cake mix label for additional allergens including soy and artificial additives.
- Tip: scatter lemon zest over the warm topping immediately after pulling from the oven — the heat releases the citrus oil into the crust surface for maximum aroma.