Dab meat dry and season with salt and pepper. Heat oil in a pan. Fry the meat for about 7 minutes, turning it once in between. In the meantime, segregate the spinach, wash and spin dry.
Wash, clean and slice the tomato. Peel onion and cut into thin rings. Wash basil, shake dry, pluck leaves from stems and chop finely. Stir basil into the mayonnaise, season with salt and pepper.
Cut the rolls in half and spread the mayonnaise on the halves. Remove meat from the pan and cut into thin slices. Spread the meat on the lower halves of the rolls and place the cheese on top.
Spread the tomato, onion and spinach on the cheese and place the top halves of the bread roll on top. If necessary, fix the rolls with wooden skewers.