I'm making my first wedding cake for my best friend, and I have never done flavored fillings in cakes. I just always do buttercream icing. She doesn't care if the filling is just buttercream, but her fiance wants a filling of some type. So, I need some suggestions of easy flavors that taste really good with white cake. I'm going to make all of my icing and fondant decorations the weekend before the wedding, so the filling needs to be something that can be made ahead of time and stored in the refrigerator. All suggestions are welcomed

What about a ganache filling?

bettercreme is awesome too. It is very light when whipped up and you can add anything to it to make flavors like strawberry cream, cookies and cream, peanut butter or chocolate mousse to name a few

With white cake I like to do a couple of fillings. Strawberry filling, with a whipped filling. I do bettercream, with some type of pudding, or cream cheese added. Its like a strawberry shortcake. Just layer the strawberry filling with the mousse on top of that, or torte the cake and alternate the fillings. Any flavor will work. I do chocolate ganache layer, with a cookies and cream mousse layer. I really don't like too much buttercream, so this is a way of lightening it up.

With white cake I've always been partial to lemon curd (either with or without white chocolate ganache), and raspberry always seems to be a classic choice, too.