Preheat your oven to 375°F / 190°C.
Chop the carrots, yams, potatoes, and onion into uniform 1-inch / 2. 5 cm pieces and place them in a large mixing bowl.
Drizzle the vegetables with olive oil, then sprinkle with fresh herbs, salt, and pepper.
Toss everything together until the vegetables are evenly coated.
Spread the seasoned vegetables in a single layer on a 9 × 13-inch / 23 × 33 cm baking dish or a large baking sheet.
Bake, uncovered, for 35 to 40 minutes, or until the vegetables are tender and lightly caramelized at the edges.
Don't overcrowd the pan. Give the vegetables plenty of space to ensure they roast and caramelize, rather than steam.
Cut all vegetables to a roughly uniform size for consistent, even cooking.
