Chop the yellow onions and mince the garlic cloves.
Add olive oil to a Dutch oven and cook the onions over medium-low heat for about five minutes until translucent.
Add garlic, oregano, and red pepper flakes, and cook for another minute.
Add vodka and let simmer for about five to seven minutes until reduced by half.
Crush the whole-peeled plum tomatoes into the pot and season with salt and pepper.
Cover the pot and bake the tomato mixture in the oven for an hour and a half.
Cook the penne in boiling salted water until al dente, about 10 minutes, then drain.
Blend the tomato mixture until smooth and return it to the Dutch oven.
Add heavy cream and fresh oregano, season with salt and pepper, and simmer for 10 minutes.
Add the cooked penne to the sauce and let it cook for an additional two minutes.
Stir in Parmesan cheese and serve with extra Parmesan and oregano.
