01 - Bring a large pot of salted water to a rolling boil over high heat.
02 - Add fettuccine or linguine and cook according to package directions until al dente, typically 8-10 minutes. Reserve 1/2 cup of starchy pasta water before draining.
03 - While pasta cooks, melt butter with olive oil in a large skillet over medium heat. Add minced garlic and sauté 1-2 minutes until fragrant and pale golden, taking care not to brown.
04 - Reduce heat to medium-low. Pour in heavy cream and whole milk, stirring constantly. Simmer gently 2-3 minutes until slightly thickened and bubbly around edges.
05 - Sprinkle in grated Parmesan, sea salt, black pepper, and red pepper flakes. Stir continuously until cheese fully melts and sauce becomes smooth and velvety.
06 - Add drained pasta to the skillet. Toss vigorously with tongs to coat noodles evenly. If sauce appears too thick, incorporate reserved pasta water one tablespoon at a time until glossy consistency achieved.
07 - Remove from heat. Fold in fresh parsley, basil, chives, and lemon zest until evenly distributed. Taste and adjust salt or pepper as needed.
08 - Divide among 4 warmed plates. Garnish with additional grated Parmesan and fresh herb sprigs if desired. Serve immediately while sauce remains creamy.