Preheat oven to 350°F. Grease and line two 9-inch round cake pans.
Sift cake flour, baking powder, baking soda, and salt in a large bowl.
Beat butter until smooth in a stand mixer or with an electric mixer.
Gradually add sugar and beat for 2 minutes on high speed.
Add egg whites slowly, beating well and scraping the bowl.
Combine vanilla extract, almond extract, milk, and sour cream in a measuring cup.
Add flour mixture and liquid mixture alternately on low speed, starting and ending with flour.
Divide batter between pans and smooth tops.
Bake 25-30 minutes until edges are lightly browned and toothpick comes out clean. Cool in pans on a wire rack for 15 minutes, then invert onto racks to cool completely.