Steam zucchini until tender, drain.
In a large skillet, melt butter. Add carrots and onion, saute until tender.
Remove from heat and stir in sour cream and soup (right out of the can). Stir in drained zucchini and half of the stuffing (approximately 2 heaping cups). Mix until stuffing is coated.
Pour into a greased 3 qt. baking dish.
Top evenly with remaining stuffing, cover with foil and bake at 350 for 35-40 minutes or until hot.