Arrange the phyllo pastry sheets, folded like a harmonica, in a buttered form. Put pieces of butter in between them. Put them to bake in the oven at 356°F (180 °C) to a nice crisp.
Pour the mixture over the well-baked sheets. Then bake it for another hour or so at 338°F (170 °C) until fully ready. Leave it to cool well, then invert onto a platter.