01 - Set the oven to 400°F and line a baking sheet with parchment paper.
02 - Place the carrots in a single layer on the prepared baking sheet.
03 - Whisk together maple syrup, olive oil, melted butter if using, salt, pepper, and cinnamon in a small bowl.
04 - Pour the glaze over the carrots and toss to evenly coat.
05 - Roast for 25 to 30 minutes, turning once halfway, until tender and lightly caramelized.
06 - Transfer carrots to a serving platter and sprinkle with chopped parsley if desired. Serve warm.