Add the pancetta to the skillet over medium-high heat, stirring occasionally, and cook for about 6 minutes. Drain the grease from the pan.
Add the olive oil, garlic, and shallots, and cook for one minute.
Add the wine, salt, pepper flakes, and clams to the pan. Toss gently and bring to a simmer.
Cover and cook for approximately 6-8 minutes until the clams open. Discard any unopened shells.
Drain the pasta, leaving a 1/4 cup of cooking water to add to the sauce if desired. Add pasta to the clam sauce. Stir gently for 1 minute.
Remove from the heat, add the butter, parsley, lemon juice, and zest.
Toss and serve immediately.
Great with an arugula salad and garlic bread.