Bright and lemony, this cake serves as the base for Martha's Meyer Lemon Anniversary Cake Assembly.
Preheat oven to 350 degrees. Butter cake pans. Line bottoms with parchment paper. Butter parchment, and dust with flour, tapping out excess; set aside. Sift together flour, baking powder, and 1/2 teaspoon salt into a medium bowl; set aside.
Put butter and 2 cups sugar into the bowl of an electric mixer fitted with the paddle attachment; mix on medium-high speed until pale and fluffy, about 5 minutes. Mix in egg yolks, 1 at a time, and zest. Reduce speed to low. Add flour mixture in 3 batches, alternating with milk. Transfer batter to a large bowl.
Put egg whites into the clean bowl of the electric mixer fitted with the whisk attachment; beat on medium-high speed until foamy. Add a pinch of salt; beat until soft peaks form. Gradually add remaining 1/4 cup sugar; beat until stiff peaks form.
Fold one-third of the egg-white mixture into batter with a rubber spatula. Gently fold in remaining egg-white mixture until just combined; do not overmix.
Divide batter among prepared pans. Bake until cake is golden and a cake tester inserted into center comes out clean. Transfer to a wire rack; let cool slightly, about 20 minutes. Invert onto rack. Remove parchment; reinvert. Let cool completely. Cakes can be refrigerated, wrapped in plastic, up to 1 day.
You will need thirty-six cups (multiply following batter ingredients by 4 1/2) of batter to complete the entire cake.Batter Amounts and Baking Times for 2-Inch Deep Square Pans: Each 6-inch: 3 cups batter, 35 minutes baking time; each 8-inch: 5 cups batter, 45 minutes; each 10-inch: 10 cups batter, 70 minutes.