How to Make It
Heat the grill to medium-high. Drizzle the onion, carrots, and tomatoes with the olive oil. Season with the salt and pepper. Arrange the vegetables on the grill and cook, turning once, until tender and just charred, 2 to 3 minutes for the tomatoes and onions, and 5 to 7 minutes for the carrots (cooking times will vary depending on the heat of the grill).