Pour into greased jelly roll pan and bake at 350°F for 25 -30 minutes.
Let cool before frosting.
Cream Cheese Frosting
Using an electric mixer, cream together cream cheese and butter on medium speed for 1 minute or until smooth with no lumps remaining.
Add in vanilla. Mix until combined.
Lower speed to medium-low and gradually add in powdered sugar. Increase speed to medium-high and beat until combined. You may not need all 4 cups or you might need more.If it gets too thick, you can add some milk to thin it down.