Peel the sweet potatoes and potatoes with a vegetable peeler, rinse under running water, and pat dry. Slice both the sweet potatoes and potatoes into medium-thick rounds. Peel and thinly slice the garlic clove and onion. In a saucepan, whisk together the milk and coconut cream. Add the parsley, nutmeg, salt, and pepper, and heat gently to let the herbs and spices infuse.

Preheat the oven to 400°F (200°C).

Rub a baking dish with the peeled garlic clove. Arrange a layer of sweet potatoes on the bottom of the dish, lightly salt, then add a layer of potatoes, salt again, and continue layering until all the ingredients are used.

Pour the hot milk mixture evenly over the gratin so all the ingredients are well covered. Sprinkle with grated cheese. Bake for 1 hour and 30 minutes.

Serve this gratin hot with a nice cut of meat, such as a pan-seared filet. This vegetable gratin reheats well.

Enjoy!