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 or other short pasta shape (Note: Original recipe called for 12 ounces, but this pasta makes plenty of sauce, so go ahead and cook the whole box)
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