Collect all the necessary ingredients for the dish. This typically includes penne pasta, vodka, heavy cream, tomato sauce, olive oil, garlic, onion, red pepper flakes, Parmesan cheese, salt, and pepper.
Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, usually around 10-12 minutes. Once cooked, drain the pasta and set it aside.
While the pasta is cooking, start preparing the sauce. Heat olive oil in a large skillet over medium heat. Add finely chopped onions and minced garlic to the skillet. Sauté until the onions are soft and translucent, and the garlic is fragrant, usually around 2-3 minutes.
Once the onions and garlic are cooked, carefully pour in the vodka. Be cautious as the alcohol may ignite briefly. Allow the vodka to simmer for a few minutes, allowing it to reduce slightly.
After the vodka has reduced, pour in the tomato sauce and stir to combine. Let the sauce simmer for about 5 minutes to allow the flavors to meld together. Then, pour in the heavy cream and stir until the sauce is smooth and well combined. Season the sauce with salt, pepper, and red pepper flakes to taste.
Add the cooked penne pasta to the skillet with the sauce. Toss the pasta gently in the sauce until it is evenly coated. Allow the pasta to simmer in the sauce for a few minutes to absorb the flavors.
Once the pasta is heated through and well coated in the sauce, remove the skillet from the heat. Transfer the Penne Alla Vodka to serving plates or bowls.
Garnish the Penne Alla Vodka with freshly grated Parmesan cheese and chopped parsley, if desired. Serve immediately and enjoy your delicious homemade pasta dish!