Preheat oven to 350. Spray a large rimmed baking sheet with cooking spray
Heat 1 teaspoon of the oil in nonstick skillet over medium high heat. Add onion, garlic, sugar, cook stirring occasionally until golden about 10 minutes.
Transfer to a large bowl. Heat the remaining 1 teaspoon of oil in same skillet. Add mushrooms and cook stirring occasionally until browned about 6-7 minutes. Add to the bowl with the onion allow to cool 5 minutes.
Stir in the beef, 1/2 cup of the tomato sauce, bread crumbs, egg whites, basil, salt, pepper. until well combined. I like to use my hands to mix it thoroughly.
Transfer mixture to the baking sheet and form into a 4x9 inch loaf. Spread the remaining 1/2 cup of tomato sauce over the top. You could use brown gravy instead of the tomato sauce if desired. Bake for 45-55 minutes.
Cut into slices. Tip: If you like a crispier textured loaf, cut slices, and place laying flat on baking sheet. place slices in broiler for about 5 minutes on each side.