First soften your 1/2 cup of butter
Then cream butter till it's light and fluffy (like shown in the image above)
Then gradually start beating in the 2 cups of powered sugar
When you're done it should look something like this
Then add in the teaspoon of vanilla extract then beat together
Pour in 2 tablespoons of milk then beat together for an additional 3-4 minutes.
When you're done the frosting should look something like this. Add food coloring if you want to.
Then Frost and decorate your baked good!