Boil a large pot of generously salted water and cook the penne pasta until al dente according to package instructions.
While the pasta cooks, heat olive oil and butter in a skillet over medium heat.
Sauté the finely chopped onion in the skillet for about 5 minutes, until softened or lightly browned.
Add the minced garlic and cook for about 30 seconds until fragrant.
Pour in the vodka and allow the sauce to bubble for 30 seconds to cook off the alcohol.
Stir in the tomato paste until the mixture is smooth and well combined.
Add the heavy cream and reduce heat to medium-low, letting the sauce warm and thicken for a few minutes.
Season the sauce with salt and pepper to taste and stir in fresh basil if using.
Drain the cooked pasta and toss it with the sauce, thinning with a splash of hot pasta water if needed.
Serve immediately topped with freshly grated parmesan cheese if desired.