Preheat oven to 425°F. Place a large rimmed sheet pan in the oven to heat.
In a large bowl, toss carrots with melted butter, brown sugar, ginger, cardamom, cayenne, salt and pepper until evenly coated.
Carefully remove the hot pan and spread carrots in a single layer with space between.
Roast 25–30 minutes, stirring once halfway, until edges are caramelized and centers are tender.
Taste and adjust seasoning. Garnish with parsley and citrus zest, if using. Serve immediately.
Notes
Spice swaps: No cardamom? Use 1/2 tsp cinnamon + a pinch of nutmeg. • Sweetener options: Maple syrup or honey work—use 2 to 2 1/2 tablespoons. • Dairy-free: Swap butter for 6 tablespoons olive oil; reduce roasting time by a few minutes if browning quickly. • Make-ahead: Roast 20 minutes; cool. Rewarm at 425°F for 5–8 minutes to finish. • Whole carrots: Peel and cut into 1/2-inch thick pieces; add 5–10 minutes to roasting time. • Salt: If using table salt, reduce slightly (it’s saltier than kosher).