What is commonly used for decorating cakes and creating detailed designs?

Royal icing is a type of icing that is particularly valued for its ability to create intricate designs and decorations on cakes. It is made from egg whites or meringue powder and powdered sugar, resulting in a smooth, hard finish that dries quickly. This unique property allows it to be piped into fine details and shapes, making it ideal for decorating cookies, cakes, and even for creating sophisticated techniques like lace work or fondant substitutes.

In contrast, buttercream, although versatile and commonly used, tends to be softer and can be more challenging to work with for ultra-fine details because it remains somewhat pliable even after setting. Whipped cream is light and fluffy but doesn't hold detailed designs well, as it can lose structure over time due to its high moisture content. A glaze, while useful for a shiny finish, is typically thinner and more suited for coating rather than decorating. Thus, royal icing stands out as the preferred choice for detailed, decorative work on cakes.