WHAT WE'RE COOKING? SWEET POTATO CASSEROLE - Thanksgiving Christmas Gluten free

40 oz or more canned Bruce cut yams, drained
1 1/2 C light corn syrup
1 1/2 C brown sugar
1/4 C unsalted butter, cubed
16 oz miniature marshmallows

Grease 1 qt baking dish. Heat oven to 350°. Place yams in large baking dish and pour light corn syrup then sprinkle brown sugar over. Dollop with butter. Mix well. Bake for 1 1/2 hours. Remove from oven and top with marshmallows. Bake for another 10 minutes or until marshmallows are lightly browned.