hrm… buttercream crusts over cos the butter in it gets hard… to keep it fluffy, you can cover your cake with a damp cloth once the buttercream has crusted over slightly and is no longer sticky. personally, i think there’s a certain kind of satisfaction when you bit into a cupcake with crusted-over frosting and then hit the moist goodness just under that. mmmm…sooo goooddd…
for chocolate icing, try chocolate buttercream!
there are many different ways of making buttercream, btw. try a few different recipes and see maybe those won’t crust over? i’ve only used the Wilton recipe thus far.