I know this may be a silly question for many of you professionals, but how do I keep my fillings from absorbing into the cake? They disappear into the cake, even if I only make it hours before. My marshmallow cream, whipped cream and my raspberry filling has done this. Should I be putting a thin layer of buttercream down first and then over it to "protect" it? I always get such helpful answers, so I'm counting on you. THANKS!