Making the pastry

To make the pastry, let the butter soften and then, in a bowl, rub it between your fingers with the flour, the egg and 3 pinches of salt.

Add the water a little at a time, mixing again but being careful not to overwork the pastry.

Once the pastry is smooth, form it into a ball and sprinkle it lightly with flour. Let it rest for at least one hour.
 

Cut the bacon into 5 mm (¼") pieces. Cook for 1 minute in the frying pan with a tablespoon of oil, then drain in a strainer.

Butter the cake or tart mold and place on the baking sheet.

Roll out the pastry as thinly as possible with a rolling pin.

Place the pastry into the mold without tearing it; push the pastry firmly against the sides.
 

Cut off any pastry that is hanging over the edges of the mould using scissors or a knife, leaving a 5 mm (1/4") overhang which you will turn over the edge.
 

Prick the bottom of the pastry with the tines of a fork so that it won't bubble up during baking.

Bake the pastry in the oven for 12 minutes at 180° C. (350° F.).
 

Using a whisk, mix together in a bowl: the cream, milk, 2 eggs, 2 egg yolks, 3 pinches of salt, and a little grated nutmeg if desired.

Place the bacon and the grated gruyère into the pastry shell.

Pour the cream mixture over top, being careful not to overfill the shell so that it doesn't overflow.

Place the quiche back into the oven and cook for another 20 to 25 minutes, checking the colour frequently. If it is browning too fast, place a piece of parchment paper or aluminum foil on top to protect it until it is cooked.

Remove from the oven and let cool to lukewarm before removing the quiche from the tart mould.

Serve the quiche on a round platter.