Heat olive oil in a Dutch oven over medium heat; add onion, ½ teaspoon salt, pepper, and red pepper flakes. Cook, stirring occasionally, until softened, about 5 minutes.
Add garlic; cook, stirring occasionally, 2 minutes.
Add vodka; cook, stirring to release browned bits from bottom of pan.
Add tomatoes and tomato paste to pan. Bring to a simmer; reduce heat to medium low. Stir
in remaining 1 teaspoon salt; simmer until flavors meld, about 25 minutes.
Cook pasta in a pot of boiling salted water until package directions for al dente.
Reserve 1 cup pasta water; set aside. Drain pasta in a colander.
Remove tomato sauce from heat. Stir cream and ½ cup Parmesan cheese until combined.
Add reserved pasta water, ¼ cup at a time, to loosen sauce.
Garnish servings with grated Parmesan cheese and herbs.