This is the recipe I used, copied straight out of my recipe list

Penne ala Vodka 

    1. Ingredients 
        1. 16 oz Penne Pasta
        2. 2 tablespoons Olive Oil 
        3. 4 tablespoons Butter
        4. 1 Onion
        5. 2 Garlic Cloves (2 teaspoons of minced garlic)
        6. 1/2 cup Vodka
        7. 1/2 cup Tomato Paste
        8. 1 1/2 cup Heavy Whipping Cream 
        9. Salt
        10. Pepper
        11. Basil (Thinly Sliced)
        12. Parmesan

    2. Instructions 
        1. Boil a generously salted pot of water for the penne and cook it al dente according to package directions
        2. Meanwhile, add the oil and butter to a skillet over medium heat
        3. Sauté the onion for about 5 minutes or until softened (ok if it lightly browns)
        4. Stir in the garlic and cook for about 30 seconds
        5. Add the vodka and let the sauce bubble
for 30 seconds or so
        6. Stir in the tomato paste until you've got a smooth mixture
        7. Stir in the cream, and reduce heat to medium-low
        8. Let the sauce warm
through
        9. I find this sauce thickens up very quickly (within a couple minutes), but feel free to cook it a little longer to thicken it up even more
        10. Season with salt & pepper as needed
        11. Stir in the fresh basil if using
        12. Toss with the drained pasta (if needed, thin the sauce out a bit with a splash of hot pasta
water prior to draining it)
        13. Serve with freshly grated parmesan cheese