Notes:
To make ahead follow same directions, but after topping the sweet potatoes, cover the dish with plastic wrap and refrigerate until ready to bake. Remove from fridge 30-45 minutes before baking, or add 5 minutes to the baking time.
Cook the sweet potatoes any way you wish. Roasting them is especially yummy. Usually I just boil them until tender and drain them. If you roast them or bake and they seem a bit dry after whipping, add a couple tablespoons of milk to the mixture