Crunch Topping:

• 1/2 cup classic white cake mix (from an 18.25 oz. box)
• 1/3 cup packed light-brown sugar
• 3 Tbsp cold butter, cut into small pieces
• 3/4 cup chopped walnuts

Cake:

• Remaining cake mix
• 1 cup sour cream
• 1 stick butter softened
• 2 large eggs
• 1 1/2 tsp vanilla extract
• 6 oz fresh blueberries

1. Heat oven to 325. Lightly coat 9 inch round cake pan with non-stick cooking spray.
2. Topping: In a small bowl put cake mix, light-brown sugar and butter into a bowl. Cut with pastry blender until mixture resembles small peas. Stir in walnuts.
3. Cake: In a large bowl with mixer on low speed beat cake mix, sour cream, butter, eggs, and vanilla for one minute. On medium speed beat two additional minutes (mixture will be thick). Fold in blueberries and put into the pan.
4. Sprinkle topping evenly over the top of the cake.
5. Bake 1 hour 10 minutes or until a wooden toothpick comes out clean.
6. Cool completely in pan on a wire rack.