Cut each chicken breast crosswise into 4-5 pieces, creating 8-10 scaloppini.* In a med-sized bowl, combine flour, salt and pepper. Coat chicken in mixture, and shake off excess flour. Bring a lg pot of salted water to a boil, add pasta, stir and cook for 7 min or until al dente. Drain and set aside. In a lg skillet over med heat, add oil and pancetta and fry 5 min, until fat begins to render. Push pancetta to the side and add chicken, sautéing until browned, approx. 2-3 min per side. Remove chicken and pancetta and set aside.
Add leeks and sauté until golden brown, approx. 2 min. Add asparagus and garlic and sauté 1 min more. Add lemon zest, juice, wine, chicken broth and butter. Add chicken and pancetta back to the pan, toss to coat, and simmer until sauce thickens slightly, approx. 2 min.
Toss with cooked pasta, season with salt and pepper, garnish with parsley leaves and serve immediately.
How to cut chicken breast into scaloppini
Start with an average-size boneless, skinless chicken breast. Hold a sharp knife at a hard angle and prepare to cut a medallion or 'scallop.'
While bringing the knife blade through, twist slightly, until almost horizontal.
This creates a curved, thin slice.
Continue with the second slice, keeping fingers behind the blade and moving them to stabilize the sliced section.
Repeat technique 1-2 more times.
One chicken breast should yield 4-5 scallopini.