Bring a large pot of water to a boil and generously season with salt. Add the pasta and cook according to the package instructions (Radiatore usually cooks in 10-11 minutes).

To a large skillet, add the olive oil and onions and cook for about 5 minutes over medium heat until the onions soften.

Add tomato paste, garlic, salt, dried basil, and red pepper flakes. Stir well and cook on low for a minute or two.

Add the vodka and cook for another minute to allow it to evaporate.

Pour in the heavy cream and bring it to a gentle simmer. Stir the Parmesan into it.

Add the cooked radiatore pasta to the sauce and mix well. Use some pasta water to thin the sauce if desired.