Preheat the Oven: Preheat your oven to 325°F (165°C). Grease and flour two 8-inch round cake pans.

Combine Dry Ingredients: In a large bowl, stir together 1 package white cake mix, 1 cup flour, 1 cup sugar, and 3/4 teaspoon salt until well mixed.

Add Wet Ingredients: Pour in 1-1/3 cups water, 1 cup sour cream, 2 tablespoons vegetable oil, 1 teaspoon almond extract, and 1 teaspoon clear vanilla flavoring. Mix to combine.

Incorporate Egg Whites: Add 4 egg whites to the mixture. Using an electric mixer on low speed, beat the batter for about 4 minutes until well combined.

Divide and Bake: Pour the batter evenly into the prepared cake pans. Bake in the preheated oven for 45-55 minutes, until light golden brown and a toothpick inserted into the center comes out clean.

Cool the Cakes: Allow the cakes to cool in the pans for 10 minutes before turning them out onto a wire rack to cool completely.

Prepare the Frosting: In a large mixing bowl, beat together 3 cups confectioners sugar and 1/3 cup unsalted butter until creamy.

Add Flavorings and Milk: Add 1 teaspoon clear vanilla flavoring, 1/2 teaspoon almond extract, and 1 tablespoon milk. Beat on high speed for 5 minutes until light and fluffy, adjusting with more milk if needed.

Level the Cakes: Once cooled, level the tops of the cakes if necessary to ensure they stack evenly.

Apply a Crumb Coat: Spread a thin layer of frosting over the cake to seal in crumbs. Refrigerate for 15 minutes to set.

Frost the Cake: Apply a thicker layer of frosting, smoothing it out with a spatula. Use remaining frosting for decorations.

Store the Cake: Store in the refrigerator if made in warm conditions or serve immediately.