Quick question, do you think a lemon buttercre would go well with a French vanilla Cake?

I think that sounds delish!!

My mom's favorite cake is a vanilla cake with lemon buttercream. I torte it to four layers and put a thin layer of raspberry puree between two of them and the buttercream in the other.

I agree. Sounds good. Last weekend, I made a plain yellow cake, added vanilla pudding and some lemon zest with lemon extract. Was delish!