-I recommend mixing on low while adding any powdered ingredients to avoid a cloud of powdered sugar or cocoa rising from the mixing bowl! Better to mix on low and then on high after ingredients are incorporated.
-I do not sift the powdered sugar, but sometimes I place the powdered sugar in the mixing bowl and mix on medium high before adding butter. This helps break up any lumps in the sugar!
-If you are using the frosting to decorate the cake (piping on decor) double this frosting recipe.