Preheat the oven to 425°F (220°C). Wash and peel the carrots. Trim the tops and tips. If carrots are thick, halve or quarter them lengthwise so pieces are roughly uniform and about 1/2–3/4 inch thick at their widest point. Pat carrots dry with a towel.

Season and glaze

Place the prepared carrots in a large bowl. Add 1.5 tbs olive oil, 1 tbs melted (or softened) butter, 1 tbs brown sugar, 1 tsp honey, 1 tsp fresh thyme leaves, 3 tsp salt, and 1/2 tsp freshly ground black pepper. Toss thoroughly so each carrot piece is coated evenly with oil, sugar and seasonings.

Roast

Arrange the carrots in a single layer on a rimmed baking sheet lined with parchment or lightly oiled. Spread them cut-side down where possible. Roast in the preheated oven for 18–25 minutes, stirring or flipping once halfway (at about 10–12 minutes). Roast until carrots are tender when pierced with a fork and edges are caramelized.

Finish and garnish

Remove the baking sheet from the oven. Immediately sprinkle lemon zest over the hot carrots and gently toss to distribute. Transfer carrots to a serving dish, taste and adjust seasoning if needed (add a pinch more salt if desired). Sprinkle chopped fresh parsley for color and serve warm.