Steps:

1. Puree half of tomatoes in food processor until smooth. Dice remaining tomatoes into 1/2 pieces, discarding cores. Combine pureed and diced tomatoes in liquid measuring cup (you should have about 1 2/3 cups). Add reserved liquid to equal 2 cups.
2. Heat oil in large saucepan over medium heat until shimmering. Add onion and tomato paste and cook, stirring occasionally, until onions are light golden around edges, about 3 minutes. Add garlic and pepper flakes; cook, stirring constantly, until fragrant, about 30 seconds.
3. Stir in tomatoes and V2 teaspoon salt. Remove pan from heat and add vodka. Return pan to mediuim-high heat and simmer briskly, 8 to 10 minutes; stir frequently and lower heat if simmering becomes too vigorous. Stir in cream and cook, about 1 minute.
4. Meanwhile, bring 4 quarts of water to boil in large Dutch oven. Add 1 tablespoon salt to pasta. Cook until just shy of al dente. Drain reserving 1/4 cup cooking water. Transfer pasta back to Dutch oven. Add sauce to pasta and toss over medium heat for 1 to 2 minutes, if sauce is too thick add reserved cooking water. Stir in basil and adjust seasoning with salt. Serve immediately, passing Parmesan cheese.