Store-bought icing is a convenient choice for frosting cakes; you can also turn it into a pourable glaze in less than a minute. Microwave it for just a few seconds to make it easier to spread, or longer to turn it into a glaze that you can drizzle on top of cakes and cookies. If you plan to use the frosting as a glaze, avoid using whipped varieties, which can break down when they're heated.
Scoop the frosting into a microwave-safe bowl.
Microwave the frosting on high for 10 seconds. Stir the frosting until it is fully combined.
Continue to microwave the frosting in 10-second intervals, stirring after each interval, until it reaches your desired consistency. One full can of frosting will require about 30 to 40 seconds in the microwave to become thin enough to drizzle.