This recipe is designed to achieve the perfect sponge texture and clean square edges seen in your photos.1.
Ingredients
For the Sponge Cake:
Flour:
2 ½ cups all-purpose flour, sifted.
Sugar: 1 ½ cups granulated white sugar.
Butter: 1 cup unsalted butter (softened at room temperature).
Eggs: 4 large eggs.
Liquid: 1 cup whole milk mixed with 1 tsp white vinegar (to make homemade buttermilk).
Leavening: 2 tsp baking powder + ½ tsp baking soda.
Flavor: 1 tbsp vanilla extract + a pinch of salt.
For the Frosting & Decoration:Cream Cheese: 200g (7 oz) softened cream cheese.
Butter: ½ cup unsalted butter (slightly cool).
Sugar: 3 cups powdered sugar, sifted.
Sprinkles: Multi-colored round sprinkles.2.
Instructions
Phase 1: Baking the Square Sponge Creaming: Beat the butter and sugar together until the mixture is light, fluffy, and pale.
Eggs: Add eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Dry Ingredients:
In a separate bowl, whisk the flour, baking powder, baking soda, and salt.
Combine: Alternately add the flour mixture and the buttermilk to the butter mixture, starting and ending with the flour.
Bake: Pour the batter into a greased and parchment-lined square cake pan. Bake at 175°C (350°F) for 30–35 minutes.
Cool: Allow the cake to cool completely in the pan before removing.
Phase 2: Preparing the FrostingWhisk the softened cream cheese and butter until smooth and free of lumps.Gradually add powdered sugar and beat on high speed until the frosting is thick and spreadable.
Phase 3: Assembly & DecorationLeveling: Slice off the domed top of the cake to create a perfectly flat surface.
Layering: Cut the cake horizontally into two even layers.
Filling: Spread a thick layer of frosting over the bottom cake layer, then place the second layer on top.
Topping: Spread a generous amount of frosting on the top. Use a spatula or piping bag to create the decorative wavy lines seen in the photo.
Final Touch: Scatter the colored sprinkles over the top.
Pro Tip for Perfect SquaresTo get those clean, professional edges:Chill the frosted cake in the freezer for 20 minutes before cutting.Use a long, sharp knife dipped in hot water (and wiped dry) between every cut.
