In a large pot, combine the drained lentils, celery and 6 cups water. Bring to a boil, reduce to an active simmer and cook for approximately 45 minutes, until the lentils are very tender.
In a 12 to 14-inch saute pan, heat the olive oil over high heat. Add the pancetta and render the fat. Add the onion, garlic and chile flakes. Stir in the tomatoes and cook a few minutes.
Once the lentils are tender, remove the celery, add salt and cook the pasta in the boiling water. Once the pasta is almost fully cooked, add the onion mixture and parsley and cook together for a few minutes. Season with salt and pepper and serve with extra virgin olive oil drizzle on top.
Recipe copyright 2000, Mario Batali. All Rights Reserved.