Reserve 1/2 cup of the dry cake mix. In a large mixing bowl, combine remaining cake mix, oil and 1 egg and beat until crumbly. Add nuts. Press into an ungreased 13x9 baking pan. In same bowl, combine remaining ingredients, along with the reserved dry cake mix; beat well. Pour over crust. Bake at 350 for 50 minutes, or until set. Cool thoroughly and cut into bars.