In a large skillet heat extra-virgin olive oil on medium heat. Add onion and garlic. Cook until tender. Spray 5 quart or larger slow cooker. Add onion and garlic and remaining ingredients. Stir to combine. Cook on low for 6 to 7 hours. Serve on pasta of your choice.
Meat can be added to the sauce if desired. Below is a meatball recipe that could be added to the sauce at the beginning of the cook time.
In a large bowl mix turkey, oatmeal, basil, black pepper, garlic cloves and eggs. Shape into 14 to 16, 2 inch balls. Press 1 small mozzarella ball into center of each meatball, sealed inside.
In a large skillet, heat oil over medium-high heat. Add meatballs; cook just until browned on all side. Add to the above sauce. Place half of the sauce in slow cooker, add meatballs and then last half of sauce. Cook as directed.