Bring a large pot of salted water to a boil and cook the rigatoni according to the package instructions until al dente. Reserve some pasta water before draining.
Heat the olive oil in a large skillet or pot over medium heat.
Add the onion and cook until softened and lightly golden.
Add the tomato paste and cook, stirring frequently, until it darkens slightly and begins to caramelize.
Pour in the vodka and stir to combine. Cook until the vodka has reduced and most of the alcohol has cooked off.
Add the cherry tomatoes and cook until they soften and begin to break down, creating a rich tomato sauce.
Reduce the heat and stir in the heavy cream. Season with salt and black pepper to taste.
Add the cooked rigatoni to the sauce and toss until evenly coated. Add reserved pasta water as needed to loosen the sauce and help it cling to the pasta.
Serve immediately.
