Cook the carrots and sweet potatoes in boiling water to cover for 10 minutes, until barely tender. Drain.
Preheat the oven to 350:F.
Combine the carrots and sweet potatoes with all the remaining ingredients except the butter or margarine. Turn the mixture into a shallow 3-quart baking dish. Dot the top with the margarine and bake for 30 minutes. If the top becomes too brown, cover with foil.