Krusteaz Cinnamon Swirl Crumb Cake and Muffin Mix offers a hard-to-top treat: A mile-high crumb topping that's buttery, sweet, and full of brown sugar and cinnamon What's not to love To make, stir this mix together with water and egg until moistened. (The batter will be slightly lumpy.) Then, spoon half into a pan and spread evenly. Sprinkle half the cinnamon topping, drop the remaining batter in small spoonfuls over it and spread to the pan's edge, sprinkle the remaining topping evenly, then...