Melt 1/2 cup butter. cool slightly, add 1 8 oz brick of cream cheese, 1 box of powdered sugar and a teaspoon of vanilla. Beat until smooth and spread on cake. I have skipped the butter when dieting and it wasn't bad. This makes a lot, but is there such a thing as too much cream cheese frosting? Lemon cake, carrot cake , chocolate fudge cake, Mexican Wedding cake (pineapple and nuts), tomato soup cake - all like this frosting.
I use less fat cream cheese - NEVER fat free. I prefer the taste of the lower fat one to regular.