Preheat oven to 350 degrees Fahrenheit. Line a sheet pan with Gefen Parchment Paper.

In a food processor, first add the eggs and water and process for a quick few seconds. Then add the flour, salt, and butter and process for less than a minute until a dough comes together.

In the prepared sheet pan, spread out the dough until you form a nice crust on the whole tray, including at least 1/4 way up the sides of the tray.

Add another parchment sheet on top, and then press another pan on top to hold the sheet down.

Bake it like this for 25 minutes.

Remove the extra pan and top parchment sheet and let the crust cool as you make the filling.

Sauté mushrooms and onion in oil until everything is softened (about 15 minutes).

Place the vegetables into the crust and spread them out.

Then prepare the custard part of the filling. Whisk all the ingredients together and pour over the vegetables, making sure it’s spread out all over the pan. I added some sliced tomatoes and chopped parsley for garnish.

Place this pan onto a larger pan (to avoid drips in the oven) and bake it all on 350 degrees Fahrenheit for 25 to 30 minutes until the filling is set and slightly golden.

Remove and let cool slightly before slicing and serving.