Step 1: Bring a large pot of generously salted water to a rolling boil. Add the pasta and cook according to package directions until it is perfectly al dente. Before draining, reserve about 1 cup of the starchy pasta water.
Step 2: While the pasta is cooking, melt 4 tablespoons of unsalted butter in a large skillet or Dutch oven over medium heat. Add the olive oil to the butter.
Step 3: Add the minced garlic to the skillet and sauté gently for 1-2 minutes until it becomes wonderfully fragrant. Be very careful not to let the garlic brown or burn, as this will make it bitter.
Step 4: If using, stir in the red pepper flakes and continue to cook for another 30 seconds to allow their flavor to bloom.
Step 5: If using, carefully deglaze the pan with the white wine, scraping up any delicious browned bits from the bottom. Let it simmer for 1-2 minutes to cook off the alcohol.
Step 6: If you desire an extra creamy sauce, add the cream cheese or mascarpone now and stir until it is completely melted and smooth into the sauce.
Step 7: Gradually add about 1/2 cup of the reserved pasta water to the sauce, stirring continuously until it reaches your desired consistency. You might need a little more or less depending on how thick you prefer your sauce.
Step 8: Drain the cooked pasta thoroughly and add it directly to the skillet with the garlic butter sauce. Toss everything together vigorously to ensure every strand of pasta is beautifully coated.
Step 9: Stir in the grated Parmesan cheese and the fresh parsley. Continue to toss until the cheese has melted, creating a rich and cohesive sauce that clings to the pasta.
Step 10: Taste the pasta and adjust the seasonings as needed, adding salt and freshly ground black pepper to your preference. If the sauce seems too thick, a final splash of pasta water can help loosen it. Serve immediately, garnished with extra Parmesan and fresh parsley.