Wash the mushrooms thoroughly (they are eaten raw) and cut into wafer-thin slices. Mix with the lemon juice so that all the mushrooms are moistened.
Wash and clean the leek and cut into thin slices. Add to the mushrooms.
Mix everything with the walnuts (medium coarsely chopped), the oil, pressed garlic, thyme, cayenne pepper and the salt and pepper or season to taste.
If you like, you can also turn it into a warm starter by placing the mushroom slices on a baking sheet and grilling them for a few minutes using the oven`s grill function. Then drizzle with lemon juice and then proceed as described above.