Arrange an oven rack to the bottom third of the oven. Preheat oven to 375ºF (190ºC).
Pour melted butter (1/2 cup) in an 11x7-inch baking dish. Sprinkle cinnamon (1 teaspoon), allspice (1/2 teaspoon), nutmeg (1/4 teaspoon), salt (1 1/4 teaspoons), and pepper (1/2 teaspoon) over the butter and mix together with a fork.
Add carrots (2 pounds) and toss to coat evenly.
Sprinkle brown sugar (1/8 cup) in an even layer over carrots.
Cover baking dish with foil and bake until carrots are tender, 20-25 minutes, stirring halfway through. Remove foil, stir carrots, drizzle with honey (2 tablespoons), and sprinkle with fresh thyme leaves (1 1/2 teaspoons). Serve.
Notes
Get that perfect glaze. As the carrots roast, the butter and brown sugar melt together and thicken. If your glaze looks thin at first, don’t worry — it will continue to thicken as it cooks and slightly as it cools.
Don’t overcrowd the pan. Spread the carrots out in a single layer so they roast instead of steam. This helps concentrate the flavor and gives you a richer, more caramelized finish.
Stir halfway through. Giving the carrots a quick toss halfway through baking ensures everything cooks evenly and gets coated in that sweet, buttery glaze.
Add brightness at the end. A small squeeze of lemon juice right before serving balances the sweetness and makes the flavors pop without overpowering the dish.