Cut the pancetta into ½ inch cubes and cook it in a skillet over medium low heat for 10 to 15 minutes, until browned and crisp. Remove to paper towels and drain.
Place the tomatoes on a baking sheet and coat with olive oil. Sprinkle with salt and pepper. Roast for 15 to 20 minutes, until soft.
Wash the lettuce leaves carefully and spin dry in a salad spinner. Stack the leaves on a cutting board and cut them crosswise into 1½ inch slices. Place them in a large mixing bowl.
Dressing: Place the egg yolk, mustard, garlic, anchovies (if using), lemon juice, salt and pepper into the bowl of a food processor filled with a steel blade. Process until smooth. With the food processor running, slowly pour the olive oil through the feed tube and process until thick. Add ½ cup grated Parmesan cheese and pulse a couple of times.
Toss the lettuce with enough dressing to moisten well. Add 1 cup grated Parmesan and toss. Divide the lettuce among 6 to 8 plates and sprinkle with pancetta and roasted tomatoes.
Notes
If you're wishing to prepare this recipe as GLUTEN FREE, just make sure that the pancetta and Dijon mustard you are using are free of gluten.