Ingredients for 12 servings:
1. 3/4 cup butter
2. 1 3/4 cups sugar (divided)
3. 3 cups flour
4. 1 1/2 cups sour cream
5. 1 1/2 teaspoons baking soda
6. 1 1/2 teaspoons baking powder
7. 2 teaspoons vanilla
8. 1 teaspoon orange zest
9. 3 eggs
10. 2/3 cup walnuts
11. 3 tablespoons cocoa
12. 1/2 teaspoon cinnamon
13. 1 cup chocolate chips

Directions:
1. Soften butter.
2. Preheat oven to 350°F.
3. Grease a 9 by 13 baking dish.
4. With an electric mixer on low speed, beat the butter and 1 1/2 cups sugar.
5. Increase speed to high and beat until fluffy.
6. Add flour, sour cream, baking soda, baking powder, vanilla, orange zest, and eggs, and beat on low to medium until well blended.
7. Spread half of the batter in the baking dish.
8. Chop walnuts and combine with cocoa, cinnamon, and 1/4 cup sugar.
9. Sprinkle over batter, and top with remaining batter.
10. Bake until a toothpick inserted in the center comes out clean, about 40-45 minutes.
11. After removing from oven, sprinkle chocolate chips over the surface of the cake.