Quiche Lorraine

• 50 g Gruyère cheese, cut in pieces (2 cm) (optional)

Pastry

• 150 g plain flour, plus extra for dusting
• 75 g unsalted butter, chilled, diced, plus extra for greasing
• ½ tsp fine sea salt
• 50 g water

Filling

• 200 g bacon cubes
• 4 medium eggs
• 50 g milk
• 100 g crème fraîche
  oder 100 g cream
• ¼ tsp fine sea salt
• 2 pinches ground black pepper