Step 1Heat a dry cast iron skillet over medium-high heat. Add the cumin and coriander seeds and roast until fragrant and lightly browned, about 1 minute, stirring with a wooden spoon. Lightly crush the roasted spices with a pestle or the back of a smaller frying pan to crack the coriander seeds.
Step 2In a bowl, combine the yogurt and stir in the toasted spices, pepper flakes, lemon zest, olive oil and salt and pepper to taste. The yogurt should be highly seasoned.
Step 1Set up your grill for indirect grilling and heat to medium-high.
Step 2In a large disposable aluminum foil pan, arrange the carrots in a single layer. Drizzle with olive oil and season generously with salt and pepper.
Step 3Place the carrots in the foil pan on the grill grate away from direct heat. Add wood chunks or chips to the coals. Close the grill lid.
Step 4Smoke-roast the carrots until almost tender, 30 to 40 minutes. Move the carrots (still in the pan) directly over the fire and grill until the exteriors are darkly browned and crusty, 5 to 10 minutes, turning with tongs to ensure even browning.
Step 5Arrange the carrots on a platter or plates. Spoon the spice-scented yogurt over them and sprinkle with thyme.