Sauté onions, bell peppers and garlic in oil 3 minutes or until tender. Cool.
Combine onion mixture with remaining ingredients, mixing lightly but thoroughly. Portion into two 8½ x 4½-inch dark nonstick loaf pans, 3 pounds veal mixture per pan. Bake in 350°F oven approx. 60 to 70 minutes to 160°F internal temperature.
Remove meatloaves from pans; let rest 15 minutes. Cut each loaf into 12 slices. For each portion: Plate 2 slices meatloaf with 1½ cups potatoes. Ladle 4 ounces Mushroom Gravy over meatloaf and potatoes.