01 - Preheat the oven to 425°F. Line a large baking sheet with parchment paper.
02 - In a large mixing bowl, toss the sweet potato rounds with olive oil and fine sea salt until evenly coated.
03 - Arrange the seasoned sweet potatoes in a single layer on the prepared baking sheet, ensuring they do not overlap to promote even crisping.
04 - Roast for 15 minutes, then carefully flip each sweet potato round. Continue roasting for an additional 12–15 minutes, or until they are golden brown and crisp at the edges.
05 - While the sweet potatoes are roasting, combine the granulated sugar and ground cinnamon in a small bowl and mix thoroughly.
06 - Remove the crispy sweet potatoes from the oven. If desired, lightly brush them with melted unsalted butter. Immediately sprinkle the cinnamon sugar mixture over the hot sweet potatoes, ensuring even distribution. Transfer the finished sweet potatoes to a serving platter and garnish with chopped fresh parsley, if using. Serve warm.