In a large saucepan combine milk, cream, nutmeg, cinnamon, salt, and pepper. Gently fold in sweet potatoes. Bring to a simmer and allow sauce to thicken.
Preheat oven to 350 degrees F.
Butter a 3-quart baking dish. Combine the bread crumbs, butter and Cheddar to make the gratin topping. Transfer the potato mixture to the baking dish and sprinkle with the gratin topping. Bake until the potatoes are cooked through, about 35 to 45 minutes.
Serve in the baking dish, garnished with chopped parsley.