Heat the olive oil in a large saucepan over medium heat. Stir in the onion and garlic; cook and stir until the onion has softened and turned translucent, about 5 minutes. Stir the tomato paste into the onion mixture, working all of the lumps out.
Return to a simmer; reduce heat to medium-low, cover and simmer 45 minutes, stirring occasionally. Add water if the sauce becomes too thick as it cooks, but remember that you'll be adding the cream soon so don't thin it too much.
Pour in the vodka and bring to a boil over medium-high heat; boil for 1 minute. Add the crushed tomatoes and tomato puree. Season with oregano, pepper, salt, thyme, parsley and rosemary.
Once the sauce has cooked stir in the cream until the consistency and colour are to your liking. Cook another 5 to 10 minutes to reheat.