Step 1: Prepare Your Cake Pans - Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper for easy removal later.
Step 2: Mix Dry Ingredients - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and kosher salt until well combined.
Step 3: Combine Wet Ingredients - In another bowl, beat the egg whites until frothy. Add the milk, softened butter, vanilla extract, and almond extract. Mix until the ingredients are thoroughly combined.
Step 4: Combine Dry and Wet Ingredients - Gradually add the wet mixture to the dry ingredients. Use a whisk or a mixer on low speed to combine until just smooth. Be careful not to overmix!
Step 5: Divide and Color the Batter - Divide the batter into three equal portions. In one bowl, add red food coloring to achieve your desired shade. In another bowl, add blue food coloring. Leave the third portion plain for the white layer.
Step 6: Bake the Cake Layers - Pour each colored batter into the prepared cake pans. Bake in the preheated oven for about 25-30 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.
Step 7: Prepare the Icing - In a mixing bowl, beat together the softened butter and cream cheese until smooth and creamy. Gradually add in the powdered sugar, vanilla extract, and almond extract. Beat until fluffy and well combined. You can also divide this icing into two portions and color one red and the other blue if desired.
Step 8: Assemble the Cake - Once the cake layers are completely cool, it’s time to assemble! Place the red cake layer on a serving plate, spread a layer of icing on top, and then add the white layer. Repeat the process with the blue layer on top. Use the remaining icing to frost the entire cake.