Crushed black pepper and red-chile flakes kick-start a fragrant, salty clam broth. The robust flavor of clams thrives on heat and spice, with pasta and pancetta acting as a buffer zone.
Bring a large pot of salted water to a boil. Add pasta, and cook until al dente. Drain, reserving 1 cup cooking water.
Meanwhile, cook pancetta in a large saucepan over medium-low heat until crisp, about 5 minutes. Transfer to a paper-towel-lined plate using a slotted spoon, and let drain.
Return saucepan to medium-low heat, and add 2 tablespoons butter, the parsley, garlic, 2 teaspoons pepper, and the red-pepper flakes. Cook until garlic is soft and lightly golden, about 5 minutes. Add wine and clams, and bring to a simmer. Cover, and cook until clams have opened, about 5 minutes (discard any unopened clams). Add linguine, reserved cooking water, pancetta, remaining tablespoon butter, and the lemon zest. Toss to combine. Season with pepper, and garnish with parsley.