For the crust: Place flour, chilled diced butter and salt in a food processor. Process using the pulse button until you get a crumb-like texture. Add the egg and cold water and process until the dough comes together. Take it out, wrap in cling-film and place in the fridge for 20-30 minutes.

Meanwhile: Finely dice the onion. Cut the leek in half length-wise, cut each half again and chop. Pour oil in a skillet/frying pan and add the onion and leek. Saute for 5 minutes on low-medium heat before adding the frozen spinach. Saute for a further 5 minutes (or until the spinach is thawed) and turn off the heat. Add seasoning and give it a good stir.

In a medium bowl whisk the milk, eggs and half and half until well combined. Cut/shred/grate the cheese.

Take out the pastry, divide into 2 pieces (when using two 7 or 8 inch pans) and roll each one out. They have to be larger than the bottom of your pans as you need to cover the sides as well.

Make sure to line the pans with baking parchment and grease the sides with butter before placing the crust pastry in. With your hands, press the pastry down and to the sides. With the back of a knife cut off the excess pastry.

Divide the filling into two equal halves and spread onto each pastry. Pour the egg mixture over and top with cheese.