Cut each potato into a perfectly square shape. Then with melon baller, scoop out the center of each potato "box". In large skillet, saute stuffing ingredients until onion is well-browned. Allow that to cool, then stuff potatoes with that. Place alll sauce ingreients in pot, bring to boil, reduce heat, cover, simmer 20 minutes. Preheat oven to 400. Place potatoes in baking dish. Pour sauce over, bake at 50 minutes until potatoes are soft.