#Make_the_crust:

In a food processor process flour, salt and cold cubed butter. process until crumbs are formed. Add cold water, process until dough is formed. Do not over mix.

Transfer the dough to a work surface, pat into a ball and flatten into a disk. Wrap in plastic and refrigerate for 30 minutes.

#Make_the_Filling:

Slice the mushrooms and onions. Heat 2 tblsp of olive oil and butter in a large pan. Sauté onion for 4-5 minutes, add crushed garlic, sauté for 1 minute. Add mushrooms, cook until the mushrooms release all of their moisture, and get well browned, about 10 minutes. Add more oil if needed. Remove from heat and set aside.

In a large bowl beat eggs, heavy cream, salt, pepper, dried oregano and nutmeg. Set aside.
spread mushroom mixture over the crust, then sprinkle the cheese evenly. pour the eggs and cream mixture.
Bake until golden brown and set, about 30-35 minutes. Allow to cool before serving.