Rainbow Butterfly Cake

Step 1
Preheat the oven to 350 degrees F (175 degrees C). Grease and flour an 8 1/2x11-inch butterfly-shaped cake pan.

Step 2
Mix flour and baking powder together in a small bowl.

Step 3
Combine sugar and butter in a large bowl; beat with an electric mixer until smooth and creamy. Add eggs and vanilla extract and mix until well blended. Add flour mixture in 2 batches, alternating with milk, beating batter briefly after each addition.

Step 4
Divide batter equally into 4 or 5 small cups and add several drops of food coloring to each cup, mixing well to color batter evenly. Layer small amounts of colored batter randomly in the prepared cake pan, using a toothpick to swirl colors gently. Continue until all batter has been added to the pan and colors have been swirled.

Step 5
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 30 to 45 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto a serving plate or cooling rack. Let cool completely.