Heat the oil in a 4-quart saucepan
or large Dutch oven
over medium heat. Add the onions
and cook until translucent, 2 minutes. Add the salt and garlic and cook until everything is soft but not browned, about 3 minutes.
Squeeze the tomatoes one by one into the pan, pulverizing them by hand, and pour in their juice, too. Add the bones, wine
, red pepper flakes
, if using, black pepper and bay leaf. Bring the sauce to a simmer
, and then reduce the heat to its lowest possible setting, and continue to cook for 8 hours. The sauce should reduce by about one-third.
Taste for seasoning and add more salt if necessary. Remove the bones and bay leaf
. If not using right away, let the sauce cool, then cover and refrigerate for up to 1 week or freeze for up to 2 months.