1. To make the dressing, combine the first 3 ingredients (through mustard) in a blender. Slowly add the oil in a thin stream; blend. Season with salt and pepper; set aside.
2. Wash lettuce, and separate leaves. For each serving, toss 5 large leaves in 2 tablespoons dressing. Place leaves on plate, stacking them largest to smallest. Top with 1 tablespoon blue cheese, 1 tablespoon diced shallot, and 1 teaspoon each tarragon and chervil leaves.