Cook onion and garlic in oil in a 12-inch nonstick skillet over moderate heat until onion is softened, then add carrots, mushrooms, and a touch of salt and pepper and cook until mushrooms are very tender, 10 to 15 minutes.
Stir in Worcestershire sauce, parsley, and 3 tablespoons ketchup, then transfer vegetables to a large bowl and cool.
Once cool add bread crumbs, milk, and eggs, to vegetables. Finally, add turkey and remaining salt and pepper then mix well with your hands.
Form into a 9- by 5-inch oval loaf in a lightly oiled 13- by 9- by 2-inch metal baking pan and brush meatloaf evenly with remaining 2 tablespoons ketchup.
Bake at 400 for 50-60 minutes or until completely cooked in the middle.
Servings 8