This one is similar to the Cinnamon Coffee Cake I have posted, but they are both so good, I didn't want to leave either one off! :-)
1 pkg yellow cake mix
3 eggs
16 oz sour cream
1/4 cup cold butter
1 cup chopped nuts
1 cup brown sugar
1 Tbs cinnamon
Pour cake mix into a bowl, remove 2/3 cup dry mix and set aside. To remaining mix add eggs and sour cream and beat for 5 minutes. Combine reserved cake mix, butter, brown sugar, nuts and cinnamon until crumbly. Pour half the batter into a greased and floured 9x13 baking pan. Sprinkle with half the topping. Pour remaining batter on top, and sprinkle with remaining topping. Bake at 350 degrees for 30-40 minutes.