Kat Lieu is the author of 108 Asian Cookies and the founder of Subtle Asian Baking. Through the decades, royal icing has been the edible glue of choice when it comes to building gingerbread houses.

Rich and dreamy American buttercream has several merits, but if you're looking for a frosting that's butter-free, both royal and regular icing can work a treat. Here's the lowdown on each option.

Royal icing is the go-to stuff for picture-perfect sugar cookies, because it makes a neat, hard and glossy finish that professional bakers and home chefs love. This icing is rich and thick and may ...