In a small bowl, combine the oregano, basil, pepper, salt, cayenne pepper, parsley flakes, and bay leaves. Set aside.
In a large skillet over medium-high heat, heat 1 Tbsp olive oil. Add sausage to pan and cook, stirring frequently, until evenly browned. Drain and transfer sausage to a large bowl.
In the same skillet, add onions and bell pepper. Saute until crisp-tender, about 3 minutes, stirring frequently. Transfer to sausage bowl.
Heat remaining 1 Tbsp olive oil. Add mushrooms and saute until browned, stirring frequently. Add sausage mixture to pan and toss to combine.
Add garlic, diced tomatoes, and tomato paste. Fill the tomato paste can with water and add that. Stir well to combine.
Reduce heat to medium-low and add fresh tomatoes. Simmer for at least 5 minutes, stirring occasionally.
Recipe by Simple, Sweet & Savory at https://www.simplesweetsavory.com/italian-sausage-spaghetti-sauce/