1. 1. Brown the Sausage: Heat the olive oil in a large skillet or Dutch oven over medium-high heat. Add the ground Italian sausage and break it up with a spoon. Cook until it’s fully browned and no pink remains, about 5-7 minutes. Drain any excess grease from the pan.

2. 2. Saute Aromatics: Reduce the heat to medium. Add the chopped yellow onion to the skillet with the cooked sausage. Saute for 3-4 minutes until the onion softens and becomes translucent. Stir in the minced garlic and cook for another minute until fragrant, being careful not to burn it.

3. 3. Simmer the Sauce: Pour in the jar of spaghetti sauce, water or beef broth, dried oregano, and red pepper flakes (if using). Stir everything together well. Bring the sauce to a gentle simmer, then reduce the heat to low, cover, and let it cook for at least 15 minutes, allowing the flavors to meld. Stir occasionally.

4. 4. Cook the Pasta: While the sauce is simmering, bring a large pot of salted water to a rolling boil. Add your chosen pasta and cook according to package directions until al dente (tender but still firm to the bite).

5. 5. Combine and Finish: Once the pasta is cooked, drain it thoroughly. Add the drained pasta directly to the skillet with the simmering sausage sauce. Toss gently to coat all the pasta evenly with the sauce.

6. 6. Serve with Cheese: Stir in the 1/4 cup of grated Parmesan cheese. Taste and adjust seasoning with salt and pepper as needed. Serve immediately, garnished with extra Parmesan cheese and fresh chopped parsley, if desired.