Preheat Oven To 350 Degrees F. 2 In A Large Heavy Skillet Cook The Onion, Celery, Carrot, Garlic, And Scallions In Butter, Over Medium Heat, Stirring, For About 5 Minutes. Cover The Skillet And Stir Occassionally Until The Carrots Are Tender, About 5 More Minutes. Stir In Salt And Pepper, Worcestershire Sauce, And 1/3 A Cup Of Ketchup. Cook For 1 More Minute. 3 In A Large Bowl, Combine The Meats, Eggs, Vegetables, Bread Crumbs, And Parsley. Form Into A Loaf And Put Into A Rectangular Baking Pan With 2-Inch High Sides. Cover The Loaf With Remaining Ketchup. 4 Bake The Meatloaf In The Oven For 1 Hour.