01 - Bring a large pot of salted water to a boil. Cook pasta according to package instructions until al dente. Reserve ½ cup pasta cooking water, then drain pasta.
02 - Melt butter in a large skillet over medium heat. Add minced garlic and sauté for 1 minute until fragrant without browning.
03 - Pour in heavy cream and bring to a gentle simmer. Reduce heat to low, then stir in grated Parmesan and pecorino cheeses until smooth and melted.
04 - Add cooked pasta to the skillet and toss to coat evenly in sauce. Adjust thickness by adding reserved pasta water gradually to reach desired consistency.
05 - Season with salt and freshly ground black pepper. Stir in chopped parsley and serve immediately, garnished with extra Parmesan and parsley if desired.