Cake Mix Coffee Cake

Ingredients
For the Cake:
1 yellow cake mix (15-18 ounce mix)
1/2 cup water
1/2 cup buttermilk
1/3 cup oil
3 eggs
3.4 ounce vanilla instant pudding mix
1 cup sour cream
For the topping:
1 cup brown sugar
1/4 cup granulated sugar
1 cup flour
2 teaspoons cinnamon
1/2 teaspoon kosher salt
1/2 cup butter
1 cup walnuts chopped

Instructions
Preheat oven to 350° degrees. In a large bowl, combine cake mix, water, buttermilk, oil, eggs and pudding mix. Beat with a mixer for about 2 minutes. Fold in sour cream. Pour batter into a greased 9x13 glass baking dish.
In a smaller bowl, combine sugars, flour, cinnamon and salt. Cut butter into small pieces and add to the sugar mixture. Mix together with a fork or pastry blender until crumbly. Stir in walnuts.
Sprinkle half of the topping over the batter. Use a knife to swirl the mixture throughout the cake. Top evenly with remaining topping.
Bake for 35-45 minutes or until a toothpick inserted into the center comes out clean.
Servings: 15