01 - Bring a large pot of salted water to a boil. Add penne and cook until al dente according to package directions. Reserve 1/2 cup of the pasta water, then drain using a colander.
02 - While pasta cooks, heat olive oil in a large skillet over medium. Add Italian sausage and cook, breaking it up with a wooden spoon, until browned and fully cooked, about 5 to 7 minutes. Remove excess fat if necessary.
03 - Add chopped onion to the skillet and cook until translucent, about 4 minutes. Stir in minced garlic and red pepper flakes, and cook for 1 minute until fragrant.
04 - Add tomato paste and stir for 1 minute. Deglaze with vodka, simmering for 2 to 3 minutes until slightly reduced.
05 - Add crushed tomatoes and season with salt and black pepper. Simmer for 8 to 10 minutes, stirring occasionally.
06 - Decrease heat to low. Incorporate heavy cream and Parmesan cheese, simmering gently for 2 to 3 minutes until smooth and creamy.
07 - Add drained penne to the sauce, tossing to coat evenly. Use reserved pasta water as needed to achieve preferred consistency.
08 - Taste and adjust seasoning. Plate hot, garnished with extra Parmesan and fresh herbs.