Preheat your oven to 425°F (220°C) and line a large baking sheet with parchment paper.
In a large mixing bowl, combine the sweet potato rounds, olive oil, salt, black pepper, and smoked paprika. Toss until each round is well coated.
Arrange the sweet potato slices in a single layer on the prepared baking sheet. Bake in the preheated oven for about 20 minutes, flipping halfway through, until they are tender and slightly crispy on the edges.
Remove the sweet potato rounds from the oven. Sprinkle the shredded cheddar cheese evenly over the rounds, then add the crumbled feta cheese on top.
Place the baking sheet back in the oven and bake for an additional 5-7 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let cool for a few minutes. Garnish with fresh parsley, thyme leaves, and a sprinkle of red pepper flakes if desired for a bit of heat. Serve warm as a delightful appetizer or side dish.