Place a heavy bottom sautoir or pan on medium-high flame. Add the olive oil and the butter. When the butter melts and becomes foamy add the chopped onions, let it saute until crispy, and do not let it brown.
Add the diced ham, mix it in, lower the flame and let it sweat for about 15 minutes, stir it occasionally.
Add the tomato sauce, mix it in, let it simmer for another 20 minutes, then add the parsley, simmer for 3 minutes, add the reduced heavy cream and the vodka, mix it all well and let simmer for 20 minutes
Check the consistency, simmer for other 10 minutes if you need to, season and mix in the cooked penne, let it simmer for 2 minutes and serve it HOT!!!
Procedure to cook the pasta: In a pasta-cooker or a soup pot, add 6 quarts of salted water and place it over medium-high flame. Bring the water to a boil, add the penne at once, lower the flame to medium, partially cover the pot, and let it cook for about 11 minutes, stirring occasionally, drain it and dress the pasta with your favorite sauce.