Chocolate Chip Ooey Gooey Butter Cake

Preheat oven to 350 degrees F. Lightly grease a 13 x 9 x 2-inch baking pan. In the bowl of an electric mixer, combine cake mix, egg, and butter. Pat into the bottom of prepared pan and set aside. Using the electric mixer, beat cream cheese until smooth; add eggs and vanilla. Add confectioners sugar and beat well. Reduce speed of mixer and slowly pour in butter. Combine thoroughly. Pour filling layer onto cake base layer and spread evenly. Sprinkle 1 cup chocolate chips and 1 cup chopped nuts on top of filling. Bake for 40 to 50 minutes. Don't be afraid to make a judgment call on the cooking time, because oven temperatures can vary. You want the center to be a little gooey.