Preheat your oven to 400ºF (200ºC).
Place the sweet potato slices in a resealable bag. Throw in the garlic, oil, butter, salt, pepper, Parmesan cheese, and Italian seasoning and shake until well coated.
Lightly butter a baking dish and arrange coated sweet potatoes into a spiral. Sprinkle with fresh thyme and a little parmesan if you like.
Roast the sweet potatoes for 30-35 minutes. Serve warm and sprinkle with fresh thyme.
