2½ pounds small rainbow carrots, scrubbed, tops trimmed to about ½”, halved
1 lemon, thinly sliced, seeds removed
Preheat oven to 450°. Whisk garlic, oil, maple syrup, harissa, and cumin seeds in a small bowl; season garlic mixture with salt and pepper.
Toss carrots and lemon with garlic mixture in a large roasting pan to coat; season with salt and pepper. Roast, tossing occasionally, until carrots are tender and lemons are caramelized, 35–40 minutes.