Filled this cake from smittenkitchen (made lemon with some lemon extract and lemon zest) with lemon curd made using this recipe for lemon curd and this method from Joy of Baking. I made some as mini cupcakes filled with the lemon curd and topped with Ina Garten's cream cheese frosting from her amazing Pineapple and Carrot Cake mixed with seedless raspberry preserves.
I also made some in a 9 in spring form pan, sliced in two layers, with the lemon curd mixed with the seedless raspberry preserves in between the two layers, topped with a simple buttercream.
The layer cake version was best, but honestly for the cake part, a yellow cake mix with the lemon adaptation would beat my implementation of the smittenkitchen recipe. Don't know what I did wrong.
However, my mom's good old lemon bars topped all of this.