Knead flour, 125 g butter in pieces, 1 ##egg## and approx. 1/2 teaspoon salt first with the dough hooks of the hand mixer, then with your hands quickly. Cover and chill for about 1 hour.
##Leek## Clean, wash and cut into thin rings. Steam covered in 2 tablespoons of hot butter for about 10 minutes. Season with salt and ##pepper##. Leave to cool.
Grease a quiche or tart dish (24 cm Ø; possibly with a removable bottom) and dust with flour. Roll out the dough round (approx. 28 cm Ø), place it in the mould and press it up at the edge. Prick the base several times.
Pre-bake in the preheated oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for approx. 15 minutes.
##cream## and whisk three eggs. Season with salt, pepper and nutmeg. Grate cheese. Mix with the leek and distribute in the mould. Pour the egg cream over it and bake at the same temperature for 30-35 minutes.