Grease & Flour a 20' jelly roll pan. Preheat oven to 350 degrees.
Mix crumb mixture (butter, flour, sugar, vanilla, and cinnamon). Set aside.
Follow pkg. directions on box for cake mix and pour in jelly roll pan. Bake 20 Minutes, then remove from oven and spread crumbs over warm cake. Bake again for another 20 Minutes. When completely cool, sprinkle with powdered sugar.