Remove stumps and wash the mushrooms in a mess of cold water and a handful of flour. So dust falls easily. Rinse. Arrange mushrooms next to each other in a square tray with opening up. I do not even crouch - they let their water. Panchetata can add them to the side of the tray. Each sponge insert piece melted blue and feta cheese. Sprinkle with spices and pour lightly with olive oil and soy sauce. You may pre-mix them. I do not put salt. Bake in a hot oven 250C 35-40 minutes. * This is a dose for 10 people.