Roma tomatoes make the best sauce. I usually buy a box of Roma tomatoes and let them get very ripe and bright red, a little soft or over ripe is best (no decay of course) Last time I bought a box I let them sit at room temperature for a week before they were ripe enough. Sometimes I cut the stem end off and squeeze out the juice and seeds right before processing. This will make a richer sauce. You can just cut them in half and puree them in the food processor (easy!)
For canned tomato I use a combination of sauce, chopped tomato and tomato paste. Two large (couple lbs each) of both tomato sauce and chopped tomato. Two small cans of paste are usually fine. It depends on how thick and rich you want it. Add water to the desired consistency. As you simmer the sauce the tomato paste will thicken as it spreads.
1/4 cup olive oil (not vegetable oil, not butter etc)
1 large yellow onion, diced
2 stalks celery, diced
1 red bell pepper, diced
1 green bell pepper, diced
4 cloves garlic, middle removed and put through a garlic press. If you don't have a garlic press smash it with a wide blade knife or something else (to release the flavor) before mincing.
1/2 Cup red wine (I use white zinfandel, a blush wine)
Salt and pepper to taste.
I use about half teaspoon black pepper.
If you use fresh Roma tomatoes you will need more salt than with canned tomato.
Heat olive oil in a large sauce pan. (I use a cast iron sauce pot) add diced vegetables and stir until translucent. Don't brown them, we just want to release the flavor.
Add the tomato sauce and chopped tomato, bring to a boil, reduce heat and simmer all day Covered. The longer the better. Stir often.
If you use the tomato paste I wouldn't add it until you cook it down some. The last two or three hours of cooking is fine as then you can get it as thick or rich as you want.
If you want to add ground meat (beef, pork, turkey or chicken) instead of meatballs, cook it separately, drain any oil, and add it after you add the vegetables. A combination of beef and pork is traditional.
Skip the meat and go vegetarian. This sauce is so good you don't have to add the meat it is purely your choice.
Alternative: Use the slow cooker. Saute the veggies in a pan on the stove in the olive oil then pour it in the slow cooker along with the wine, Italian seasoning, salt pepper etc. Cook for the day. You can add the meat that morning or make the meatballs in the evening and add them.
I would hold off on the tomato paste until evening if you use it.
If you make our wonderful meatballs, add them early in cooking for best flavor. You can add them last or just serve them on the pasta and pour the sauce over the top. Either way it's all good!
The sauce is good fresh. Don't be afraid to freeze leftover sauce or serve it the next day because this is when the flavors are at their best. You could also make it a day or two ahead of time. Then when you heat it up the flavor is at it's peak.