Best Slow Cooker Tomato Spaghetti Sauce

I've been making this spaghetti sauce
for over thirty years,it's the best.

Ingredients:
1 lb bulk Italian pork sausage
1 Ib ground beef 85/15
2 large onions, chopped (2 cups)
2 cups sliced fresh mushrooms (6 oz)
4 cloves garlic, finely chopped
1 can (28 oz) diced tomatoes, undrained
2 cans (15 oz each) tomato sauce
1 can (6 oz) tomato paste
1 tablespoon dried basil leaves
1 teaspoon dried oregano leaves
1 tablespoon brown sugar
1/2 teaspoon salt or to taste
1/2 teaspoon pepper
1/2 teaspoon crushed red pepper flakes
4 bay leaves

Directions:
Spray 5-quart slow cooker with olive oil cooking spray.
In 12-inch skillet, cook sausage, onions, mushrooms
and garlic over medium heat about 10 minutes,
stirring occasionally, until sausage
is no longer pink; drain.
Spoon sausage mixture into cooker.
Stir in remaining ingredients.
Cover; cook on Low heat setting 8 to 9 hours
or until vegetables are tender.
Remove bay leaves before serving.