Heat oven to 325°F. Grease sides of two 9- or 8-inch round cake pans. Line bottoms of pans with cooking parchment paper. In medium bowl, beat cake flour, 3/4 cup sugar, the baking powder, salt, shortening, milk, vanilla and 4 egg yolks with electric mixer on low speed 30 seconds, scraping bowl constantly. Beat on high speed 2 minutes, scraping bowl occasionally. (Batter will be stiff.) Spread evenly in pans.