Cut the butter into small pieces. Knead butter, 1 pinch of salt, 2-3 tablespoons of water and flour first with the dough hooks of the hand mixer, then work into a smooth dough with your hands.
Wrap dough in cling film and chill for about 20 minutes. Peel onions and cut into fine cubes. Halve the leek lengthwise, wash and cut into approx. 1/2 cm wide strips. Fry the diced bacon in a frying pan.
After about 4 minutes, add the onion cubes and sauté for another 2-3 minutes. Add the leek and remove the pan from the heat. Grate cheese. Mix milk, cream and eggs. Flavour egg-milk with salt, pepper and nutmeg.
Roll out dough round (28 cm Ø) . Grease a quiche tin (25 cm Ø) and line it with the dough. Cut off any protruding edges. Spread the onion-bacon-porree-mix on the base. Sprinkle with cheese.
Pour egg milk over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 30 minutes. And here is the video for ##Quiche Lorraine##!