Heat the oven. Preheat to 425°F (220°C).
A hot oven is key for caramelization and tender centers.
Prep the carrots. Peel and trim the carrots. Cut into uniform sticks about 1/2 to 3/4 inch thick and 2 inches long. Even sizing helps them cook at the same rate.
Make the glaze. In a large bowl, whisk together olive oil, honey, salt, pepper, and, if using, garlic and thyme. If your honey is thick, warm it slightly so it mixes smoothly.
Toss to coat. Add the carrots to the bowl and toss until every piece is glossed with the honey mixture.
Spread on a sheet pan. Line a rimmed baking sheet with parchment for easy cleanup.
Arrange the carrots in a single layer with space between them. Overcrowding leads to steaming, not roasting.
Roast and turn. Roast for 15 minutes. Remove the pan, stir or flip the carrots, and spread them out again. Return to the oven and roast another 10–15 minutes, until tender with browned edges.
Finish with acid. While still hot, drizzle with lemon juice and toss.
Taste and adjust seasoning with a pinch more salt or pepper if needed.
Garnish and serve. Sprinkle with chopped parsley and serve warm. The glaze will thicken as it cools, so bring them to the table promptly.