This multi-flavored, multi-layered cake is truly a labor of love.
Whisk together flour, baking powder, and salt in a medium bowl.
Beat butter and sugar with an electric mixer on medium speed until light and fluffy, about 5 minutes.
Credit: Photo: Victor Protasio; Prop Styling: Cindy Barr; Food Styling: Torie Cox
Add eggs and egg yolks, 1 at a time, beating well after each addition.
Add flour mixture to egg mixture alternately with milk in 5 additions, beginning and ending with flour mixture.
Beat on low speed until just combined after each addition.
Divide batter evenly among 3 greased and floured 9-inch round cake pans.
Bake in preheated oven until a wooden pick inserted in center comes out clean, 23 to 25 minutes.
Cool in pans on wire racks 10 minutes.
Remove Cake Layers from pans to wire racks; cool completely, about 30 minutes.
When cool, gently slice each layer in half horizontally, making 6 thin layers.
With mixer running on low speed, gradually add powdered sugar, and beat until smooth.
Add vanilla, salt, and 3 tablespoons of the milk; beat until smooth, about 1 minute.
(Add up to 1 tablespoon more milk, if needed to reach desired consistency.)
Remove and reserve 1 cup of frosting in a small bowl.
Divide remaining frosting evenly between 2 medium bowls.
Stir lemon zest and juice into 1 medium bowl of frosting.
Stir in yellow food coloring to achieve desired color.
Add cocoa to remaining medium bowl of frosting, and stir until smooth.
Place chocolate and remaining 1 tablespoon milk in a small microwavable bowl.
Microwave on HIGH until chocolate melts and mixture is smooth, about 20 seconds, stirring every 10 seconds.
Cool 5 minutes, and stir into chocolate frosting.
Place 1 Cake Layer on a serving plate.
Spread about 13 cup lemon curd on half of layer.
Spread about 13 cup chocolate pudding on the opposite half.
Repeat process with 4 more Cake Layers.
Top with remaining layer.
(Indicate on a sticky note which flavor is on each side, and attach to serving plate.)
Spread 1 cup reserved plain frosting in a thin layer over sides.
Spread lemon frosting over top and frosted sides of lemon half of cake.
Spread chocolate frosting over top and frosted sides of chocolate half of cake.
