What's the difference between a crusting buttercream vs. a regular buttercream?
The crusting buttercream will firm up. You can literally touch it and it will feel hard.
The difference is the ingredients. Usually crusting buttercreams are made with powdered sugar mixed with butter and or shortening. (Some are made with both and some are made with one or the other). Non crusting buttercreams are usually made from egg whites, granulated sugar and butter.
Because of the ingredients, the texture of the two are different. Crusting buttercreams do just that, they crust over. After they sit out for a bit, they dry up and you can touch it without any of the buttercream coming off on your finger. Non crusting buttercreams don’t dry up like that.
There is a taste difference as well as a difference in how the two smooth so it really just comes down to personal preference. Some people can’t stand trying to smooth and crusting buttercream and others can’t manage to smooth a meringue (egg white) buttercream. So it’s just a matter of trying both and seeing what you like.
I guess with that said I use a crusting buttercream, my recipe is the Wilton one with butter and shortening. Yes, I hate smoothing it out but I am slowing figuring it out.