I am getting ready to make a cake one tier will be a citrus cake with buttercream and lemon curd filling. The other a watermelon cake with ?? hmmmmm... What kind of buttercream flavor and filling would go best? I am at a loss.

try mixing a unsweetened watermelon kool-aid mix into your regular buttercream. mix it to taste. it's sort of sour, but tastes reallllly good

I'll try that for the filling TY. I think I am going to make my buttercream with Italian Sweet Cream coffe creamer to try and get that whipcream taste to it.
My mom will be getting out of the hospital this week and is Watermelon crazy. So we are having a get together and I want to surprise her with a watermelon cake.