Put the plain flour and cubed butter in a mixing bowl. Rub them together to form a coarse crumb.
Add the egg. Cut through with a knife to combine.
Add 1-2 tbsp of water, cutting through with the knife until the mixture starts to clump.
Knead the pastry into a dough.
Place the pastry on a floured surface and roll out to about 5mm thick.
Cut out 12 rounds. You may need to gather up the offcuts and re-roll.
Place the rounds on your 12-hole muffin tray.
Press the rounds into the tray. Use your thumb to push the edges up to the top of the holes and ensure there’s no air stuck under the pastry. It's a good idea to pop the whole tray in the refrigerator for 10 minutes to chill, if you have time. This will help ensure your cases don't shrink during baking.
Share the vegetables between the twelve pastry cases.
Put the milk and eggs in a bowl. Whisk.
Share the egg mixture between the twelve pastry cases.
Sprinkle the grated cheese on top.
Sprinkle with the fresh chopped parsley.
Bake for about 10 minutes until the pastry is golden and the filling is firm.
Allow to cool slightly before serving. They can be enjoyed hot or cold.
The beauty of these quiches is that you can add any other veg you like. Try frozen, fresh or even seeds and pulses.