Preheat oil in a deep sauce pan to 130 ° C. During cooking try to keep temperature around this value. Higher temperature will burn bread crumbs quickly, but lower temperature will not be sufficient for quick and effective cooking. Place mushrooms into hot oil and cook for about 2-4 minutes. It is possible to spot, how they will shrink in size and the batter around the cheese start to breaks. This is a good sine that mushrooms are ready.