Place the Italian sausage in a large, heavy-bottomed saucepan and brown over medium heat, breaking it up as you stir.
Add the chopped onion and continue cooking, stirring occasionally, until the onions soften.
Add the minced garlic and cook for 1 minute.
Add the diced tomatoes, tomato paste, tomato sauce, and water.
Add the basil, parsley, brown sugar, salt, crushed red pepper flakes, and black pepper.
Stir well and bring the sauce to a gentle boil.
Stir in the red wine.
Reduce heat to low and simmer for at least 1 hour, stirring frequently to prevent burning.
Cook the spaghetti in a separate large saucepan according to package directions.
Drain the spaghetti using a colander.
Spoon the sauce over the spaghetti and sprinkle with parmesan cheese.
Notes
Tips and Tricks
Brown the Sausage Well - Let the sausage develop a nice brown color before adding the onions. This adds more depth to the sauce.Don't Rush the Simmer - The recipe calls for at least an hour of simmering, but 90 minutes to 2 hours makes the sauce even better. Just stir it frequently and add a little water if it gets too thick.A large, heavy-bottomed saucepan distributes heat evenly and prevents the sauce from burning on the bottom during the long simmer.Use Quality Tomato Products - Since tomatoes are the base of this sauce, using good-quality canned tomatoes makes a noticeable difference in flavor.Taste and Adjust - Before serving, taste the sauce and adjust the seasonings. You might want to add more salt, red pepper flakes, or a pinch of sugar to balance the acidity.Cook Pasta Al Dente - Cook the spaghetti until it's just barely tender. It should have a slight bite since it will continue to soften when mixed with the hot sauce.Reserve Pasta Water - Save a cup of the starchy pasta water before draining. You can add a splash to the sauce if it's too thick or to help the sauce stick to the noodles better.Let It Rest - If you have time, let the finished sauce sit for 10 to 15 minutes before serving. This helps the flavors settle and the sauce thickens slightly.
Storing
Refrigerate - Store the sauce and pasta separately in airtight containers in the refrigerator for up to 4 days.Freeze the Sauce - Freeze the sauce in freezer-safe containers or bags for up to 3 months. Don't freeze cooked pasta as it gets mushy.Portion for Easy Meals - Divide the sauce into individual portions before freezing so you can thaw only what you need.
Reheating
Reheat on Stovetop - Place the sauce in a saucepan over medium-low heat. Stir occasionally and add a splash of water or broth if the sauce is too thick. Heat until warmed through.Reheat in Microwave - Place a serving of sauce in a microwave-safe bowl. Cover loosely and heat in 1-minute intervals, stirring between each, until hot.Reheat Pasta - Drop the cooked pasta in boiling water for 30 seconds to 1 minute, then drain and top with reheated sauce.