Preheat the oven to 350°F.
Cut the sweet potato into chunks and boil in lightly salted water for about 15 minutes or until the pieces are tender. Drain and return to the saucepan.
Mash potatoes with a potato masher, adding the butter, milk and cinnamon. Season to taste with salt and pepper.
Spoon mashed sweet potatoes into a shallow 1 quart casserole and smooth the top. Add either of the toppings listed below. Bake in preheated oven for 20 minutes.
1 loaf sourdough or crusty bread or 2 cups prepared bread crumbs
1/2 cup parmesan cheese
1 teaspoon dried thyme
Remove crusts from the bread and break it into small pieces. Process in the food processor until you have crumbs. Mix in the parmesan cheese and thyme. Spread evenly over the top of the sweet potatoes.
For those who would rather have the traditional recipe for sweet potato marshmallow casserole, top with miniature marshmallows, spread evenly over the top of the casserole. Bake as directed.
2 cups prepared bread crumbs
3 tablespoons butter, softened
1 cup pecan halves or pieces
Prepare bread crumbs as in the recipe above, then mix with the softened butter and pecans. Spread evenly over the top of the sweet potatoes and bake as directed.