Potato gratin with minced fish

Ингридиенты: 
  • 500 grams of mushrooms,
  • 1 kg potato
  • 2 onions,
  • 3 tbsp. tablespoons butter,
  • salt, pepper, spices to taste,
  • 4 eggs,
  • 2 tbsp. spoons of mayonnaise,
  • grated cheese.