In a skillet over medium heat, heat the butter. Add the finely chopped onion and cook until soft, about 5 to 7 minutes. Stir in the minced garlic and cook for 1 more minute.

Pour in the dry white wine and let it reduce for about 30 seconds. Stir in the tomato paste and heavy cream. Allow the sauce to simmer for around 5 minutes until it begins to thicken.

Remove the skillet from the heat and mix in the grated Parmesan cheese. Season with red pepper flakes (if using) and salt and pepper to taste.

Serve the sauce immediately, tossing it with cooked pasta.