Black Walnut Butterscotch Cake

1 (18.25 ounce) box yellow cake mix
1 (21 ounce) can butterscotch pudding
1 (12 ounce) package butterscotch bits
2 eggs
1 cup chopped black walnuts

Combine cake mix, eggs, pudding; mix well. Beat on medium speed 2 minutes. Pour into greased and floured 13 x 9 x 2-inch pan. Spread butterscotch bits evenly over top, then add black walnuts. Bake at 350 degrees F for 30 to 40 minutes or until wooden pick inserted in middle comes out clean.