• 

  Gruyère cheese or Swiss cheese (optional), cut into pieces (3 cm)

  50 gram

Pastry

• 

  butter, unsalted or salted (from cows' milk) cut into pieces, plus extra for greasing

  75 gram
• 

  wheat flour plus extra for dusting

  150 gram
• 

  salt

  ½ teaspoon
• 

  water

  50 gram

Filling

• 

  bacon cube

  200 gram
• 

  olive oil (optional - see Tips)

  20 gram
• 

  egg (from chicken)

  4
• 

  cow milk

  50 gram
• 

  crème fraîche, min 30% fat or pouring (whipping) cream

  100 gram
• 

  salt

  ¼ teaspoon
• 

  black pepper, ground

  2 pinch