Caramel Pecan Dream Bars

1 (18.25 ounce) box yellow cake mix
1/3 cup softened margarine
1 beaten egg
1 can sweetened condensed milk
1 egg
1 teaspoon vanilla extract
1 cup chopped pecans or walnuts
1/2 cup Heath bits or 1 Heath bar, chopped

Mix together cake mix, margarine, and beaten egg. Pat into a greased 13 x 9-inch cake pan and set aside.

Mix the condensed milk, egg and vanilla extract together. Beat well. Stir in the nuts and Heath bits. Pour over crust and bake at 350 degrees F for 25 minutes. Cool and cut into bars.