Bring a large pot of salted water to a boil. Once boiling, add the sweet potato chunks and cook 10-15 minutes, or until the sweet potatoes are fork tender. Check at 10 minutes.
Remove from heat and drain well.
Combine the sweet potatoes chunks into a food processor (or large mixing bowl with a potato masher on hand) with remaining ingredients listed and process (or mash) until it reaches a creamy consistency and no chunks remain. Add the milk, as needed, to reach a creamy consistency.
Adjust seasonings to taste when it comes to sugar, salt, and cinnamon. Start by adding a dash of cinnamon at a time. A little goes a long way.
If you love sweet potatoes with a marshmallow topping: Pour the mashed sweet potatoes into a casserole dish, top with marshmallows and place in the oven under broil on LOW. Bake until the marshmallows have melted and just starting to brown on the top.
CINNAMON: Start with a dash of cinnamon when pureeing. A little goes a long way. You don't want to add too much.MILK: Add 1-2 tablespoons at a time until you reach the perfect creamy consistency. You don't want them to be runny!BROWN SUGAR: I added 1/4 cup to give it a subtle sweet taste. If you like yours more on the sweeter side, add 1-2 tablespoons more at a time and taste test as you go.