In medium bowl add flour, brown sugar, oats, and cinnamon. Cut cold butter in slices and cut into mixture with pastry blender or fork until it resembles a crumb topping.
Drain yams and put in a 2 quart casserole pan. Wash cranberries and drain well. Add cranberries to yams in casserole pan. Toss in 1 cup of Crumb Topping and toss lightly. Add the remaining Crumb Topping.
Bake at 350 degrees F for 35-40 minutes until bubbling. Remove from oven and Sprinkle 1-1/2 cups Kraft Mini Marshmallows on top of casserole and return to oven. Bake until marshmallows are lightly golden brown, watch carefully that marshmallows don't burn. Remove from oven, cool for 5 minutes and serve.