Sift flour onto a work surface making a mound. Put egg, diced butter and salt into the central hollow. Work the ingredients quickly with your hands until you have a smooth mixture and let it sit for about an hour in the refrigerator.
Roll out the cold dough with a rolling pin into a sheet of 3 mm in thickness, place in a buttered and floured mould, press, perforate several times with a fork and with a spatula or the back of a knife, remove the part of dough that sticks out from edge of the mould. Precook it in an oven at 180° C for about 10 minutes.
Brown the bacon in a frying pan. In a bowl, mix the eggs with crème fraîche and milk, then season with salt, pepper and nutmeg.
Distribute the bacon rashers over the pastry, next add the emmental and cover with the mixture of eggs and milk. Bake the quiche in the oven at 180° C for about 35 minutes.