- Set oven to 350F.
- Wash sweet potatoes, then slice them up using a mandolin or sharp knife. They should be the thickness of about 2 nickels. Add them to a bowl.
- Sprinkle in nutmeg, cinnamon, smoked paprika and arrowroot and toss. Make sure every slice is coated.
- In a baking dish or cast-iron skillet, lightly spray with cooking spray, then arrange a single layer of overlapping sweet potatoes in the bottom. Add a bit of parmesan and then pour in some of the coconut milk. Repeat.
- On the final top layer add the gouda and rosemary.
- Cover with foil and bake in the oven for 50 minutes, removing the foil about halfway through in order to brown the top.
- Let it cool for at least 20 minutes before enjoying. The longer it has to cool, the thicker and creamier it will be upon serving.