Bring 4 quarts water to boil in a large pot. Meanwhile, process half of tomatoes in food processor until smooth. Transfer to bowl. Stir in vodka and remaining tomatoes.
Heat oil in large skillet over medium heat until shimmering. Add onion and sun-dried tomatoes and cook until onion is softened, about 3 minutes. Add garlic, red pepper flakes and italian seasoning and cook until fragrant, about 30 seconds. Stir in tomato-vodka mixture and 1/2 teaspoon salt and simmer until slightly thickened, 8 to 10 minutes. Add cream and cook until heated through, about 1 minute.
Meanwhile, add 1 tablespoon salt and pasta to boiling water and cook until al dente. Reserve 1/2 cup cooking water, drain pasta, and return to pot. Add sauce and toss to combine, adding reserved pasta water as needed. Season with salt and pepper. Serve.