# Ingredient List:
→ Sponge Cake
01 - 2 3/4 cups all-purpose flour
02 - 1 1/2 cups granulated sugar
03 - 2 1/2 teaspoons baking powder
04 - 1/2 teaspoon salt
05 - 1 1/8 cups unsalted butter, softened
06 - 4 large eggs
07 - 1 cup whole milk
08 - 2 teaspoons vanilla extract
09 - Food coloring gels (red, yellow, green, blue, purple)
→ Buttercream Frosting
10 - 1 1/2 cups unsalted butter, softened
11 - 4 cups powdered sugar
12 - 3–4 tablespoons milk
13 - 2 teaspoons vanilla extract
14 - Pinch of salt
# Directions:
01 - Preheat oven to 350°F (180°C). Grease and line five 8 x 8 inch square baking pans, or plan to bake in batches if fewer pans are available.
02 - In a large bowl, beat the softened butter and granulated sugar together until light and fluffy. Add eggs one at a time, beating well after each addition, then incorporate the vanilla extract.
03 - In a separate bowl, whisk together the all-purpose flour, baking powder, and salt until evenly mixed.
04 - Alternately add the flour mixture and milk to the wet ingredients, beginning and ending with the flour mixture. Stir gently until just combined to avoid overmixing.
05 - Evenly divide the batter into five separate bowls. Add a different gel food coloring to each portion, mixing until uniformly tinted.
06 - Pour each colored batter into a prepared pan and spread evenly. Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out clean.
07 - Allow cakes to cool in their pans for 10 minutes before transferring to wire racks to cool completely.
08 - Beat the softened butter until creamy. Gradually add powdered sugar, vanilla extract, and salt, mixing until the frosting is fluffy. Add milk a tablespoon at a time until desired consistency is reached.
09 - Trim the edges of each colored cake and slice into uniform 1 1/4 inch squares.
10 - Arrange the colored squares in an alternating pattern on a large tray to create a patchwork effect. Use a thin layer of buttercream between pieces to bond them. Build multiple layers by repeating the pattern.
11 - Apply a thin layer of buttercream over the top and sides of the assembled cake. Smooth the surface carefully, optionally piping additional lines with buttercream to enhance the patchwork design.
12 - Refrigerate the finished cake for 30 minutes before slicing and serving to allow frosting to set.