BASIC YELLOW CAKE

Steps:

• Preheat oven to 350 degrees, with racks in upper and lower thirds. Cut two 9-inch rounds of parchment paper to line the bottoms of two 9-inch (2 inches deep) round cake pans. Butter and line pans. Butter linings. Dust pans with flour, tapping out excess. Set aside.
• Sift together flour, sugar, baking soda, baking powder, and salt into the bowl of an electric mixer. Return bowl to mixer; fit mixer with the paddle attachment. Add eggs, yolk, water, buttermilk, oil, and vanilla. Mix on low speed until mixture is smooth, about 3 minutes.
• Divide batter evenly between prepared pans. Bake, switching positions of pans and rotating halfway through, until a cake tester inserted into centers comes out clean, about 42 minutes. Let cool in pans on wire racks 30 minutes. Run a thin knife around edges of cakes to loosen. Unmold; peel off parchment. Let cool completely, top sides up, on racks.
• Trim tops of cake layers with a long serrated knife to make them level. Using a small offset spatula, evenly cover top of one cake layer with 1 1/2 cups frosting; spread frosting so that it extends just beyond edges of cake.
• Place second cake layer, cut side down, on top; press gently to make it level. Frost top and sides of assembled cake with remaining frosting.