1. Prepare the Blueberry Filling

Preheat your oven to 170°C (340°F). In a large mixing bowl, start by combining the granulated sugar with lemon zest. This helps release the lemon’s aroma and flavor. Add the blueberries next, sprinkling in the cornstarch and lemon juice. Stir until the blueberries are evenly coated and the mixture looks juicy. Pour this fruit filling evenly into your baking dish so every bite of cake gets that fruity flavor.

2. Make the Cake Topping

In another mixing bowl, combine the flour, sugar, baking powder, and salt by whisking them together. Make sure these dry ingredients are well blended. Add the cold pieces of butter to the bowl. Use a pastry cutter, fork, or your fingertips to gently work the butter into the dry mixture until it looks like coarse crumbs. Do not overmix. Then stir in the vanilla powder and milk, just until everything is moistened. The batter should be slightly lumpy, not smooth like regular cake batter.

3. Assemble the Dump Cake

Using a spoon, drop dollops of the cake topping over the blueberry filling. Try to spread the topping evenly, though it can be a bit rustic looking. It’s totally fine if a few blueberries remain visible through the topping. This uneven layering is part of what makes dump cakes fun and easy.

4. Bake

Place your baking dish in the oven and bake for 40 to 50 minutes. You want the top to turn a nice golden brown and the blueberry filling to be bubbling around the edges. The smell while it bakes is amazing, like summer in the oven!

5. Serve

Once baked, let the cake cool for a few minutes so the filling thickens a bit. Enjoy it warm, topped with a scoop of vanilla ice cream or a spoonful of whipped cream, if desired. The contrast between the warm, fruity base and the creamy topping is incredible.