Options for fillings, there is no measurements here, but it is safe to assume 1/2 to 1 cup of each. The goal is layer in the fillings then pour the milk and egg mixture over that to fill up the pie crust, if feeding a crowd, use two pie crusts and different fillings for each: Spinach, chopped Onion, sliced Mushrooms, Broccoli, cubed and cooked Ham, Bacon, chopped Bell Pepper, chopped Tomatoes, other types of Cheese, you get the idea.

Preheat your oven to 200 C. Line a cookie sheet with foil. If using a frozen ready made pie crust, thaw that before you preheat the oven. Place the pie crust in a pie pan and set aside.

Whisk together the milk and mayo until smooth, then whisk in the eggs.

In a skillet with just a splash olive oil, heat up the spinach and onion until the onion is just soft. If using other items, cook those as well until almost cooked through.

Add the spinach and cheese in layers in the pie crust, making several layers of each. Pour the milk mixture over the filling until the pie crust is not quite full to the top. Place the pie dish on the cookie sheet, cover the pie dish with foil and bake for 45 minutes, remove the foil and bake for another 10-15 minutes or until the top is golden brown. Remove from oven and let rest for a few minutes, serve.