Heat the olive oil in a 4-quart saucepan until it shimmers.
Add the garlic, onions, and serrano and sauté until soft and translucent, but not brown.
Stir in the tomato paste and let it sauté for a minute.
Slowly whisk in the wine (or broth, if using instead) and then add the crushed tomatoes, oregano, and salt.
Bring to a low boil, turn down the heat, and simmer for 20 minutes.
Yields a generous 3 cups of sauce.