Carrot Stuffing Casserole

4 cups sliced, cooked and drained carrots
1 can cream celery soup
1 chopped onion
1/2 cup (1 stick) melted margarine
1 cup sharp shredded Cheddar cheese, divided
1 box chicken flavored stuffing mix

Mix together carrots, soup, onion, margarine, 1/2 cup of the Cheddar cheese and stuffing mix. Put into greased 2-quart casserole. Top with remaining 1/2 cup Cheddar cheese. Cover and bake at 350 degrees F for about 30 minutes.