How to make
Peel the onion and saute it in the butter. Add the cleaned and chopped mushrooms. Saute briefly. Season with salt, black and white pepper.
Smear a cake form with removable sides with butter. Form the base of the pie using the phyllo pastry sheets and raise the edges a bit.
Pour in the filling. Use a pastry brush to smear the edges with mayonnaise. Sprinkle generously with grated gouda (or cheese).
Bake in a preheated 392°F (200 °C) oven with the fan on for 10 min. Garnish the ready pie with olives. Appetizing and crunchy!