Prepare the crust by combining flour, salt, and cold butter in a food processor until it resembles breadcrumbs.

Add grated Parmesan cheese and water, pulse until the dough comes together.

Knead the dough slightly and wrap in plastic wrap. Refrigerate for 30 minutes.

Preheat oven to 200 degrees C.

Sauté garlic, shallots, and mushrooms in a pan until softened and water evaporates. Season with salt.

Add pepper, parsley, and garlic powder to the mushrooms and stir well.

Roll out the dough into a 1/4 inch thick disc.

Drape the disc over your pie pan and press it in.

Spread a layer of mozzarella cheese over the crust.

Add a layer of cooked mushrooms.

Pour the beaten eggs on top.

Sprinkle some cheese on top.

Bake at 180-190 degrees C for 30 minutes or until the custard is set.