Place chicken between 2 sheets of heavy plastic on a solid, level surface; firmly pound with the smooth side of a meat mallet to an even thickness. Season generously with salt and pepper.Advertisement
Pour flour into a large, flat dish. Beat eggs thoroughly in a shallow bowl. Pour bread crumbs into another large, flat dish.
Dredge each piece of chicken in flour, dip in beaten eggs, and coat with bread crumbs.
Preheat oven to 200 degrees F (95 degrees C).
Heat oil in a large skillet over medium-low heat. Cook breaded chicken in batches until golden brown and no longer pink in the center, about 5 minutes per side. Drain on an ovenproof plate lined with paper towels. Keep warm in the oven.
Spread mayonnaise over bottom half of each sandwich roll; top with 1 piece of breaded chicken, a few drops of lemon juice, 1 dash hot sauce, and 1 lettuce leaf. Spread mustard over the top half of each sandwich roll. Place top halves over lettuce to form sandwiches.
If you have leftover schnitzel, it tastes great cold in this sandwich. Also tastes great with tomatoes, pickles, banana peppers, alfalfa sprouts, or cucumbers. Add as many vegetables as you like.