01 - Bring a large pot of salted water to a boil. Add fettuccine or spaghetti and cook until al dente, following package timing. Reserve 1/2 cup pasta cooking water before draining the noodles.
02 - Melt unsalted butter in a large skillet over medium heat until foamy. Add freshly ground black pepper and swirl for 30 seconds to release aroma.
03 - Transfer drained noodles to the skillet. Toss well to coat with butter and pepper.
04 - Pour in half of the reserved pasta water and sprinkle with sea salt. Toss continuously, adding more pasta water as needed for a glossy, cohesive sauce.
05 - Remove skillet from heat. Add grated parmesan and toss vigorously until fully melted and sauce is creamy.
06 - Sprinkle lemon zest, chopped parsley, fresh chives, and crushed red pepper flakes if desired. Toss gently to combine.
07 - Taste and adjust seasoning with additional salt or black pepper as needed. Serve immediately with extra parmesan grated on the side.