Heat ¼ cup olive oil in a large sauce pot over medium heat. Add pancetta and cook for about 4 to 5 minutes Add onion and cook for about 7 minutes or until translucent, stirring frequently. Toss in garlic and cook for another 2 minutes. Add the tomatoes.
Season with salt and pepper. Add oregano, basil, thyme and Parmesan rind. Cover and reduce to low and cook for 2 to 3 hours. Taste throughout to see if you need to add more salt or herbs. Remove Parmesan rind and use immediately or freeze.
Do not skip cooking the pancetta, as it gives the sauce added flavor.
If you can’t find tomato puree, San Marzano tomatoes will work as well.
You can use fresh herbs, but will have to triple the amount for each herb used as dried herbs are much stronger.
Don't skip the Parmesan rind. I always save the rinds and put in the freezer to be able to use for recipes just like this. It adds a little nutty flavor that can't be topped.
Cook this marinara sauce for at least 2 hours so you can develop the flavors.