Preheat oven to 400 F. Place a silicone baking mat or parchment paper into rimmed baking sheet.
In a small mixing bowl, toss the baby potatoes and veggies with the olive oil and seasoning salt.
In a large mixing bowl, combine the ground beef, egg, bread crumbs, minced onion, and Worcestershire sauce. Form into a round flat loaf, no taller than 1 1/2".
Place the meatloaf in the centered of the baking dish and drizzle ketchup over the top, coating well.
Spread the baby potatoes and veggies, with the oil and seasoning salt, around the meat loaf in a single layer.
Bake in the pre-heated oven for 30 to 35 minutes, or until potatoes are tender and meatloaf is cooked through. The cooking time may vary depending on size of potatoes and height of meatloaf. I've found 35 minutes to be plenty for a loaf that's 1 1/4-inch to 1 1/2-inch tall.
Serve Sheet Pan Meatloaf with Potatoes and Veggies.