Combine first 5 ingredients, mixing well.
Spoon mixture into a lightly greased 1 1/2-quart casserole.
Cover and refrigerate 8 hours or overnight.
Remove from refrigerator; let stand 30 minutes.
Bake, uncovered, at 350Â° for 25 minutes.
Remove from oven, top with marshmallows.
Bake an additional 7 minutes or until marshmallows are golden.