Peel carrots and trim the ends. Cut on a deep diagonal into ½-inch slices, or leave small carrots whole. Keep cuts consistent — same size means even cooking. Toss in a large bowl with a drizzle of olive oil until coated. Season well with kosher salt and black pepper. Add herbs or spices now if using (thyme, rosemary, garlic). Toss to coat evenly. Line a rimmed baking sheet with foil and lightly oil it.

Preheat oven to 425°F (or 400°F for a gentler roast). Spread seasoned carrots in a single layer on a baking sheet — no touching or overlapping, or they'll steam instead of brown. Use two pans if needed. Roast at 425°F for 25–35 minutes, or at 400°F for 35–40 minutes. Toss every 10 minutes for even browning on all sides. For a glaze, add it in the last 5–10 minutes. Toss to coat and return to oven until absorbed and caramelized.

Carrots are done when edges are browned and caramelized and a fork slides in easily with little resistance — tender throughout, not mushy. Still firm? Return to oven in 5-minute increments. Hard carrots usually mean undercooking, too-low heat, or uneven cuts. Transfer to a platter. Finish with lemon juice, a drizzle of olive oil, or fresh herbs (parsley, dill, or cilantro). Optional: crumbled feta or truffle oil. Serve hot. Refrigerate leftovers in an airtight container for up to 4 days.