Hi, @sweets74! This is the closest recipe we could find - it comes from our friends at the Pillsbury Bake-Off. I hope this will help!
Toffee Nut Squares
BASE
1 pkg. Pillsbury Plus Yellow Cake Mix
1/2 cup Parkay® margarine or butter, melted
1 egg
TOPPING
1 cup firmly packed brown sugar
1 teaspoon vanilla
2 eggs
2 tablespoons flour
1 teaspoon baking powder
1/2 teaspoon salt
1 cup coconut
1/2 cup chopped walnuts or pecans
Heat oven to 350°F. In large bowl, combine cake mix, margarine and 1 egg at low speed until well blended. Press in bottom of ungreased 13x9-inch pan. Bake at 350°F. for 10 minutes.
Meanwhile, in same bowl combine brown sugar, vanilla and 2 eggs; blend well. Add flour, baking powder and salt; mix well. Stir in coconut and walnuts. Carefully spread topping evenly over warm base. (Topping must touch sides of pan.)
Bake at 350°F. for an additional 20 to 25 minutes or until golden brown and
topping is set. Cool; cut into bars.