in a skillet large enough to hold the cooked pasta, melt the butter over medium heat. Add the garlic and cook until golden, about 2 minutes. Stir in the prosciutto and cook for 1 minute.
Add the tomatoes and crushed red pepper and simmer for 5 minutes. Stir in the cream and cook, stirring well, for 1 minute. Add the vodka and cook for 2 minutes. Season to taste with salt.
Meanwhile, bring at least 4 quarts of water to a boil in a large pot. Add the pasta and salt to taste. Cook, stirring frequently, until the penne is al dente, tender yet still firm to the bite. Drain the pasta, reserving some of the cooking water.
Add the pasta to the skillet with the sauce and toss the pasta until it is well coated. Add a little of the reserved cooking water if the sauce seems too thick. Add in the cheese and toss again. Serve immediately.