Prick the pie crust a few times all over with a fork, then fit it with foil and fill with baking beads. Blind bake for 15 minutes at 425F / 220 C and then remove the foil and beads and bake for a further 10 minutes until golden brown. Remove from the oven and allow to cool for 20 minutes.
Fry until cooked and slightly browned, stirring through some fresh thyme, salt and pepper. Remove from the heat. Then in a bowl, whisk together the eggs, milk, cream and nutmeg and season with salt and pepper.
Put half the grated cheese at the bottom of the pie crust, then half the mushrooms layered on top. Ladle in half of the milk/cream mixture (if you just slosh it in you'll lose the layers) and then repeat.
Put back in the cooler oven for 40 minutes or until the filling looks set and not too loose when you jiggle it slightly..
Place on a cooling rack and leave to rest for 20 minutes before enjoying with a nice green salad simply dressed.