Royal icing is a hard, matte icing made by beating powdered sugar with egg whites (or meringue powder) and sometimes a little lemon juice, used mainly for cake and cookie decoration rather than as a frosting to eat by the spoonful. It dries into a brittle shell, which is what makes it useful for piped designs, lettering, and structural work like gingerbread houses or securing tiers on a stacked cake. The "royal" name comes from its use on Queen Victoria's 1840 wedding cake, though egg-white-based icings existed earlier. It's flavor-neutral and mildly sweet, so it takes well to citrus or spice flavoring without clashing with the cake or cookie underneath; a stiffer mix pipes fine detail, while a thinned-out version is used to flood and fill in outlines.