1) Preheat oven to 365
2) Mix all ingredients except last 3.
3) Pour into a greased 9x13 pan
4) Bake the cake for 30-35 min or until toothpick comes out clean
5) Meanwhile mix the frosting with an electric mixer (last three ingredients:melted butter, lemon juice and powdered sugar)
6) Spread frosting evenly across cake with a spatula. Make sure the frosting is well absorbed
7) Let cool before cutting