Prepare the pans. Preheat the oven to 350°F. Generously coat three same-size 8- or 9-inch round cake pans with cooking spray. Line the bottoms with parchment paper and spray again for easier removal.
Cream the butter and sugar. Using a stand mixer fitted with the paddle attachment or a large bowl and hand mixer, beat the softened butter and sugar on medium speed for 2 to 3 minutes, or until light and creamy.
Add the egg whites. Add the room-temperature egg whites in three additions, mixing until incorporated after each addition. Mix in the almond extract and scrape down the sides of the bowl.
Finish the batter. In a separate bowl, whisk together the flour, baking powder and salt. Add the dry ingredients to the butter mixture in three additions, alternating with the room-temperature milk in two additions. Begin and end with the dry ingredients, mixing on low speed just until combined after each addition. Avoid overmixing.
Create the candy corn colors. Divide the batter evenly among three bowls, using a kitchen scale if possible. Leave one portion white, tint one yellow and tint the third neon orange. Add the food coloring a little at a time until the colors resemble candy corn.
Bake the layers. Transfer each color of batter to a prepared cake pan and spread it into an even layer. Bake for 20 to 25 minutes, or until a toothpick inserted into the center comes out clean. Begin checking 9-inch layers at 20 minutes.
Cool and level the cakes. Let the cakes cool in their pans for 5 minutes, then turn them onto wire racks to cool completely. Once cool, use a serrated knife to trim any rounded tops so the layers will stack evenly.