Preheat the oven to 425°F and line a rimmed baking sheet with non-stick aluminum foil or parchment paper.
In a large mixing bowl, toss the prepped sweet potatoes with the olive oil. Try to coat as evenly as possible. Spread potatoes on the prepared baking sheet in a single layer.
Bake the sweet potatoes for 20-30 minutes (this is largely dependant on the size of your fries), flipping fries half way through. To test, pierce with a fork and wait until they are tender.
In a small bowl, toss together the Parmesan cheese, garlic, parsley, thyme, and salt.
Remove from the oven and spoon the Parmesan cheese mixture evenly over the sweet potato fries.
Increase the oven temp to broil, return the baking sheet and watch closely. Remove when the cheese is melted and edges begin to brown.
Serve hot!
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