Heat the oil in a large Dutch oven over medium heat. Add the ribs and brown evenly, about 4 minutes. Add the onions, sprinkle with salt and cook until translucent, 2 minutes. Add the garlic and cook until everything is soft but not browned, about 3 minutes.
Add the white wine, stirring to deglaze the pan. Add the tomatoes along with the oregano, red pepper flakes if using, bay leaf and Parmesan rind. Bring the sauce to a simmer, reduce the heat to its lowest possible setting and continue to cook until reduced by about a third, for up to 8 hours.
Taste for seasoning and add more salt if necessary. Remove the bay leaf. If not using right away, let the sauce cool, and then cover and refrigerate for up to 1 week or freeze for up to 2 months.
Tip: This sauce freezes well, so you can make big batches, portion it into smaller containers and freeze it for when you need it.