01 - Bring a large pot of generously salted water to a rolling boil. Add the fettuccine or spaghetti and cook according to package directions until it reaches an al dente texture. Before draining, reserve ½ cup of the starchy pasta cooking water. Drain the pasta thoroughly.
02 - In a large skillet, melt the unsalted butter with the olive oil over medium heat. Add the minced garlic and gently sauté for 1 to 2 minutes, or until the garlic becomes aromatic but avoids browning to prevent bitterness.
03 - Pour the heavy cream into the skillet with the garlic. Bring the mixture to a gentle simmer, stirring occasionally, and allow it to cook for 3 to 4 minutes to slightly reduce and thicken.
04 - Stir in the grated Parmesan cheese, salt, freshly ground black pepper, and red pepper flakes (if using). Continue to stir until the Parmesan cheese has fully melted and the sauce achieves a smooth, creamy consistency.
05 - Add the drained pasta directly into the skillet with the sauce. Toss gently to ensure every strand is thoroughly coated. If the sauce appears too thick, gradually add the reserved pasta water, a tablespoon at a time, until your desired consistency is achieved.
06 - Remove the skillet from the heat. Stir in the freshly chopped parsley, incorporating it evenly throughout the pasta and sauce.
07 - Portion the creamy garlic pasta onto serving plates immediately. Garnish generously with additional grated Parmesan cheese and a sprinkle of extra chopped parsley before serving.