1. Wrap sweet potatoes in tin foil and bake for an hour to an hour and a half until soft all the way through.

2. When done cooking, scoop the insides into a bowl.

3. mash in the cinnamon, brown sugar, butter or syrup, and vanilla. Mash until relatively creamy and all the big chunks of potato have been broken up.

4. Spread evenly in a casserole pan. Cook for half hour at 350 degrees.

5. Take out the casserole, cover it with the marshmallows, and increase oven to 450. Cook casserole until marshmallows are brown.