Christine, there is a recipe I’ve been wanting to try from the Pie & Pastry Bible that seems like it would be perfect for upscale twinkie filling, particularly if you don’t want the tanginess of cream cheese or marscapone (though those sound great to me!).
Rose calls it “Rich Whipped Cream Filling” and it starts out like a swiss buttercream, with beaten egg yolks/ soft ball sugar syrup, then beating in butter, but then the recipe folds in whipped cream after that. Sounds like it would be lighter than classic buttercream, yet more substantial and flavorful than whipped cream. Yum!
It is the filling for the Danish Waffle Creams, p.443 of the PPB.