In a large saucepan over medium-low heat, add butter, oil, balsamic vinegar, mushrooms and onions. Season with salt and cover. Cook, stirring occasionally, until veggies are tender. Stir in garlic and cook another minute.
Add ground meat to the veggies and cook until browned. Add remaining ingredients and stir to combine. Break up tomatoes with spatula. Cook sauce over a low simmer, stirring occasionally, for a minimum of 15 minutes.
Serve Mushroom Spaghetti Sauce over a bed of spaghetti and with your favorite salads and garlic breads.
Notes
* Nutrition information are just estimates and not exact measurements.