Preheat oven to 375F/190C. Take goat cheese out of the fridge and let it soften at room temperature.

Spray a 3-4 quart glass casserole with with non-stick spray or olive oil. I used an oval 4-quart baking dish, but any 3-Quart Baking Dish (affiliate link) would have been big enough.

Peel the sweet potatoes and cut into slices about ¼ inch thick. (Don't make them too thick or they will take longer to cook.)

Put the softened goat cheese in a small bowl, add the half and half and the thyme, and whisk together until it's smooth. (You can put the package of goat cheese in the microwave and heat in 10 second intervals until it's soft to make this easier to mix.)

Layer half the sweet potatoes in the baking dish and season well with salt and fresh-ground black pepper.

Spread half the goat cheese mixture over the sweet potatoes and sprinkle on half the grated Parmesan.

Make another layer each of sweet potatoes seasoned with salt and pepper, goat cheese mixture, and Parmesan.

Cover the dish tightly with foil and bake 1 hour (or until the sweet potatoes are quite soft when you stick a fork in them.)

Remove foil and bake 20 minutes more, until the sweet potatoes are very soft and the top is nicely browned. Serve hot.

This will stay good in the fridge for several days and may have reheated a little too well, if you know what I mean.

I haven't tried it, but I'm sure the dish could be assembled in advance, refrigerated, then allowed to come to room temperature when it comes out of the fridge and baked later in the day, or possibly even the next day.