Buttery cinnamon crumb topping is the crowning glory to this flavorful cake that starts with a simple cake mix.

 

Makes 24 servings.

Prep Time: 20 minutes

1/2 cup flour

1/2 cup firmly packed brown sugar

4 teaspoons McCormick® Cinnamon, Ground

1/2 cup (1 stick) butter, melted

1 cup chopped walnuts

1 package (18 1/4 ounces) white cake mix

1 egg

1 cup sour cream

1/4 cup (1/2 stick) butter, melted