Rinse the romaine lettuce, let the leaves drain well and cut them into coarse pieces. Peel the garlic and mince it very finely. Grate the Parmesan cheese and juice the lemon.
Season the chicken breast fillet on both sides with salt and pepper. Heat a skillet and pan-fry the chicken for approximately ten minutes until golden brown on all sides and cooked through. Remove the chicken fillet from the pan, let the meat rest for a minute on a cutting board and then cut it into strips.
Beat the egg in a large bowl. Add the two tablespoons of olive oil, the fresh lemon juice, the minced garlic and half of the grated Parmesan cheese. Whisk this mixture vigorously until a smooth dressing forms and season with salt and pepper to taste.
Add the coarse pieces of romaine lettuce to the bowl and toss well so the dressing coats all the leaves. Place the prepared salad on a plate. Distribute the cut chicken strips over the lettuce and sprinkle with the remaining Parmesan cheese.