How to Make It
Heat oven to 400° F. In a medium bowl, combine the beef, bread crumbs, ketchup, grated onion, bacon, garlic, egg, ½ cup of the Gruyère, ½ teaspoon salt, and ¼ teaspoon pepper. Transfer the mixture to an 8-by-4-inch loaf pan and sprinkle with the remaining ¼ cup of Gruyère.
Meanwhile, on a large rimmed baking sheet, toss the onion wedges and carrots with the oil, ½ teaspoon salt, and ¼ teaspoon pepper.
Roast the meat loaf until cooked through, 40 to 45 minutes. Pour off any accumulated fat and let rest 10 minutes before slicing. At the same time, roast the vegetables, tossing once, until tender, 35 to 40 minutes.
Slice the meat loaf and serve with the vegetables and additional ketchup.