Preheat oven or air fryer to 350°.
Add broth or water to a skillet or frying pan over medium heat. Saute the onion, bell pepper (if used), garlic, salt, pepper, thyme, basil and oregano with the broth/water for about 10 minutes or until the liquid has evaporated. Remove from heat and cool to room temperature.
While the onion mixture is cooling, cover a jelly roll pan or other rimmed baking sheet with aluminum foil and lightly mist with olive oil (non-aerosol).
In a medium sized bowl, combine beef, egg, onion mixture, ½ of the tomato sauce and melba toast crumbs (if using).
Mix well and form into one large or two smaller loaves and place on the foil line pan.
Top loaves (loaf) with the remaining tomato sauce and place in the oven for about 35 minutes. Remove from oven and serve.