Preheat the oven to 400°F. Combine the butter, olive oil, garlic, salt, herb seasoning, thyme, and all but 2 tablespoons of the cheese in the bottom of a large mixing bowl. Stir to combine. Add the sweet potatoes and toss gently to coat.
Lightly grease the bottom and sides of 2 medium baking dishes or casserole dishes with olive oil. Arrange the sweet potatoes in the baking dishes, tucking them together like shingles to fit into the pans. Sprinkle each dish with 1 tablespoon Parmesan cheese.
Bake for 30-40 minutes or until potatoes are tender. Serve warm.