No.

Frosting is obtained by processing powdered sugar, so there is a difference between powdered sugar and frosting. Frosting is a sweet decoration for cakes and other baked goods. It is a smooth, creamy white product made from crystallized sugar syrup and is used as an exterior icing for some cakes such as Napoleon shortbread, finger shortbread, and frosted cupcakes, as well as a glossy, non-sticky coating on the surface of the cake. Most of the time, powdered sugar in pastry making materials can be replaced with powdered sugar such as lanugar, but not when sprinkled on the surface of cakes, cookies, etc.

Expanded Information:

Note:

Obeseed and people with high blood lipids should not consume more powdered sugar.

The increase in the amount of sugar added, so that the anti-hydration of sugar to enhance the role of the cookie dough at the same time make the protein water absorption rate decreased, seriously affecting the formation of gluten, and therefore in the rise of more sugar rise good, less sugar rise poor, less sugar, not fluffy enough, the texture of the dense on the hard to cook ah. I'm not sure if it's a good idea, but I'm sure it's a good idea.

Baidu Encyclopedia - Frosting

Baidu Encyclopedia - Powdered Sugar