Pasta alla Vecchia Bettola

Name: Pasta alla Vecchia Bettola
Prep time: 30 min
Cook time: 2 h
Total time: 2 h 30 min
Cuisine: American
Ingredients: 1/4 cup good olive oil; 2 1/2 cups chopped Spanish onion (1 large); 1 tablespoon minced garlic (3 cloves); 1/2 teaspoon crushed red pepper flakes; 1 1/2 teaspoons dried oregano; 1 cup vodka; 2 28-ounce cans peeled plum tomatoes; Kosher salt; Freshly ground black pepper; 1 pound penne rigate; 2 tablespoons chopped fresh oregano, plus extra for serving; 1 cup heavy cream (or less, to taste); 1/2 cup freshly grated Parmesan cheese, plus extra for serving