SWEET POTATOES WITH CRANBERRIES

3 lbs. sweet potatoes
1 1/2 lbs. fresh berries
1 1/2 lbs. granulated sugar
Butter as needed

Cut the potatoes into 1 inch cubes. Place half of them in a buttered baking pan and cover with half of the cranberries. Sprinkle on half of the sugar. Repeat this process with remaining ingredients. Cover the pan. Place in a 350 degree oven and bake for approximately 30 minutes until cranberries pop open. Remove cover and bake another 20 minutes until potatoes are tender.