preheat oven to 375°F - your baking the sauce for an hour and a half
Heat the oil in a medium Dutch oven over medium-low heat. Add the onions and cook for about 5 minutes, until the onions are translucent. Add the garlic, dried oregano and the red pepper flakes and cook for another minute. Add the vodka and simmer for 5-7 minutes, until it is reduced by half. Using your clean hands, crush each of the plum tomatoes into the pot. Add 2 teaspoons kosher salt and a ½ teaspoon black pepper. Cover the pot with the lid and bake for 1½ hours.
During the last half hour bring a large pot of salted water to boil and cook the penne according to the directions on the box. Drain and set aside.
Once the tomato sauce has been cooked add it to either a food processor or a blender as you need to puree the sauce until smooth. Return the tomato mixture to the pot. Add the fresh oregano, cream and 1 teaspoon salt and a ½ teaspoon black pepper and simmer partially covered for 10 minutes. Add the cooked pasta to the sauce and cook for 2 more minutes. Remove from the heat and add a ½ cup of Parmesan cheese and serve immediately.