Season the beef meat and pepper. Mix the mixture well, press about 2 cm high, flatten. Cook on the grill. Press the flat key again.
Shitake or oyster mushrooms in oil. Cut the breadcrumbs lightly. Place lettuce leaves on the bottom of the bread roll with truffle mayonnaise. Place the hot bread on lettuce and spread with dijon mustard. Put 2 slices of Appenzeller® cheese on top. Then place fried mushrooms on the cheese.
Decorate with onion rings and truffle mayonnaise. Finally, place the bean sprouts on the burger and cover with top of the bun.