Preheat your oven to the temperature specified in the cake mix package, usually around 350°F (175°C). Prepare your cake pans by greasing and lightly flouring them.

In a large mixing bowl, combine the cake mix, vegetable oil, and egg whites. Add the almond extract and mix on medium speed for about 2 minutes until well combined.

Pour the batter evenly into your prepared cake pans, ensuring no air pockets remain. Bake for 25-35 minutes or until a toothpick inserted comes out clean.

While the cake bakes, prepare the frosting. In a saucepan over medium heat, combine flour and milk, whisking until thickened. Let cool before beating with softened butter and powdered sugar.

Once baked, allow the cake layers to cool in their pans for 10 minutes before turning them onto wire racks to cool completely.

Once the cake layers are cool, spread a layer of buttercream frosting on top of one layer before gently placing the second layer over it. Frost the top and sides of the cake.