Place carrots in 2-quart microwave-safe casserole. Wash and trim Brussels sprouts. With tip of knife, cut an X in base of each sprout. Place on top of carrots. Add water; cover. Microwave on HIGH for 10 to 15 minutes or just until tender, stirring once halfway through cooking.
Drain carrots and Brussels sprouts well. Add margarine and dill weed. Cover; let stand 5 minutes. Mix gently to coat vegetables.