01 - Bring a large stockpot of generously salted water to a rolling boil. Add the pasta and cook according to package directions until al dente. Before draining, reserve 1/2 cup of the starchy pasta water, then thoroughly drain the pasta.
02 - While the pasta cooks, melt the unsalted butter with the extra virgin olive oil in a large skillet or Dutch oven over medium heat. Add the minced garlic and sauté gently for 1 to 2 minutes, until aromatic but without allowing it to brown.
03 - Carefully pour in the heavy cream, stirring continuously to incorporate. Bring the mixture to a gentle simmer and cook for 3 to 4 minutes, allowing the sauce to slightly reduce and thicken.
04 - Stir in the freshly grated Parmesan cheese, black pepper, salt, and red pepper flakes (if desired). Continue stirring until the cheese has fully melted and the sauce is smooth and homogeneous.
05 - Add the thoroughly drained pasta directly into the skillet with the sauce. Toss vigorously to ensure every strand is coated. Gradually add the reserved pasta water, a tablespoon at a time, until the sauce reaches your desired creamy consistency.
06 - Stir in the majority of the finely chopped fresh flat-leaf parsley, reserving a small amount for final garnish. Taste the pasta and adjust salt or pepper as needed to achieve perfect seasoning.
07 - Serve the pasta immediately, garnished with the remaining chopped parsley and an extra sprinkle of freshly grated Parmesan cheese.