Heat 2 tbsp olive oil and 2 tbsp butter in a large skillet over medium heat. Add chopped onion and cook until soft and translucent, about 5 minutes. Stir in the minced garlic and red pepper flakes, cooking for another 1-2 minutes until fragrant.
Stir in 2 tbsp of tomato paste and cook for 5-7 minutes, stirring frequently, until the paste darkens and thickens. This step helps develop the rich tomato flavor of the sauce.
Pour in ¼ cup of vodka, stirring to combine. Let it simmer for 2-3 minutes until most of the alcohol cooks off and the mixture reduces slightly. This process helps smooth out the sauce.
Lower the heat to medium-low and pour in 1 cup of heavy cream. Stir constantly to blend the cream into the tomato mixture. Allow the sauce to simmer gently for 5 minutes, letting it thicken.
Stir in ½ cup of freshly grated Parmesan until fully melted and the sauce becomes smooth and creamy. Taste and season with salt and black pepper as needed.
If the sauce is too thick, add a splash of pasta cooking water until you reach your desired consistency. Simmer for another 5-10 minutes on low heat to let all the flavors meld together.
Toss the sauce with your cooked pasta until well coated. Serve immediately with an extra sprinkle of Parmesan cheese and fresh basil, if desired.