3/4teaspooncrushed red pepper flakesor more to taste
2tablespoonsbutter
1cupreserved pasta water
1/2cupgrated Parmesan cheese
Kosher saltto taste
Fresh basilwhole leaves or thinly sliced, for garnish
Instructions
Bring a large pot of salted water to a boil. Add the shell pasta and cook until al dente per the package instructions. Reserve 1 cup of the pasta water before draining.
In a large skillet over medium heat, warm the olive oil. Add the diced onion and sauté for 2 to 3 minutes until soft. Then add the minced garlic and cook for another minute.
Stir in the tomato paste and cook for 2 minutes to deepen its flavor. If using, add the vodka and let it cook for 1 minute so the alcohol evaporates.
Pour in the heavy cream and add the crushed red pepper flakes. Stir until the sauce thickens, about 2 minutes. Then mix in the butter and some of the reserved pasta water to reach your preferred sauce consistency.
Add the drained pasta to the skillet and stir until it is well coated. Fold in the grated Parmesan cheese and season with salt, adjusting to taste. Serve hot, garnished with fresh basil.