Drain Sweet potatoes. In a mixer or by hand mash sweet potatoes until soft and smooth, add remaining ingredients and blend by hand or in mixer. Pour into a 9 x 13 greased pan. Bake at 425 for 15 min.
At the same time, mix topping ingredients to form a chunky mixture. Do not blend! mixture should be stuck together in large clumps.
Remove casserole from oven, sprinkle top with topping, cover with foil, turn oven to 325 and bake 30 minutes. turn oven to 350 and remove foil bake an additional 15 minutes. remove from oven to trivet and let stand 5 minutes before serving.
Note: Fresh, raw sweet potatoes can be used. Aprox 8-10 Large Sweet Potatoes... Bake 1 hour, scrape pulp of sweet potato from skin, discard skins, and prepare as above. Increase prep time by 15 min and cooking time by 1 hour.
Note: This can be made up to 2 days ahead of time, refrigerate, reserve adding the topping until after the first bake cycle so it doesn't get soggy. Bake an additional 15 minutes before topping is added. It can be frozen without topping, thawed and baked as if it were refrigerated. add topping after first baking cycle.