"An homage to my time spent in Austria. Something you might find on a snack cart on the street in Austria or Germany. A tender chicken schnitzel inside a crusty sub roll with lettuce, mayo, lemon juice, and mustard. A simple and delicious sandwich that can be made with leftovers if desired! Goes perfectly with a beer and a handful of chips."
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.
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.