In my family on Christmas morning you can always count on there being crumb cake, but usually of the sour cream variety. The recipe we usually use if from my grandmother, it has a dense crumb made with oats, and the cake has a unique tang from the added sour cream. The recipe is our go to for Christmas morning sweets to nibble on as we open our presents! This year I decided to buck our family tradition (Sorry family!) and try a new variety of crumb cake.