Mix egg yolk and iced water lightly together in a bowl, using a fork.
Using a food processor fitted with a steel blade, process flour, salt, and butter for 10 seconds or until crumbs form. Add egg and water mixture and process until pastry forms a ball (do not over-process).
Alternatively, rub butter quickly and gently into flour and salt using your fingertips or a pastry blender, until mixture resembles coarse breadcrumbs. Sprinkle over egg and water mixture and, using a knife or spatula, mix until absorbed and dough forms a ball.
Preheat the oven to 200-220°C.
Roll out pastry to a circle just larger than the loose-based pan (23-25 cm diameter) and sides. Lift pastry onto a rolling pin and drape it gently over the pan. Ease into the pan, pressing the pastry into the base of the pan, towards the middle, and into the sides (this helps to prevent stretching). Roll the rolling pin over the top of the pan to trim off the excess.
Prick well over the base with a pricker or skewer. Place the lined pan in the freezer for at least 10 minutes, or until needed, and bake it from frozen.
Placing the pastry case as close to the heat source as possible (for a crisp result), bake for 15 minutes. Remove from oven. (Pastry should be firm and a pale golden colour.) Leave to cool in the pan on a rack before filling and baking.
Sauté the bacon and onion in butter until brown. Drain if necessary, and sprinkle evenly in the prepared pastry case.
Whisk the eggs and cream (use an extra 125 ml (1/2 cup) if desired) together in a bowl, salt lightly and add pepper and nutmeg.
Pour the egg mixture into the pastry case, to three quarters full, to allow room for expansion. Bake at 180-200°C for 15 to 20 minutes, or until the mixture has firmed.
Add remaining egg mixture and bake for a further 15 to 20 minutes. The top should be puffed up and golden.
To test if it is cooked, insert a fine metal skewer into the centre of the filling. It should come out clean.
Remove and serve immediately with a salad.