In the bowl of an electric mixer, add the softened butter (or vegan butter) and whip on high until light and fluffy. Add powdered sugar and vanilla extract and beat slowly at first, then increase speed to high and beat for 2-3 minutes. You may need to add in a teaspoon or two of milk to thin the frosting out, but it depends on how you like it. Enjoy as is or fold sprinkles into the frosting with a spatula to make birthday cake frosting!
