Cut the chicken fillet into small pieces and fry in a small amount of oil until golden brown.
Grate the cheese on a coarse grater.
Cut the mushrooms into several pieces if they are too large. Today I had oyster mushrooms. But you can also use any others that you like more.
Mix all the ingredients and add the peas.
Mix sour cream and horseradish, adding a little salt. Who likes it sharper, can add more horseradish. Season the salad with this sauce, mix and put in a salad bowl.