Leek quiche

Pastry

• 300 g plain flour
• ½ tsp fine salt
• 150 g butter, cold, diced, plus extra for greasing
• 1 egg yolk
• 50 g water, ice cold

Filling

• 200 g Gouda cheese or any other medium-hard cheese, cut into pieces
• 150 g cooked ham, cut into pieces
• 200 g double cream
• 4 eggs
• ¼ tsp freshly ground black pepper
• 1 ½ tsp fine salt
• 1 pinch ground nutmeg
• 400 g leeks, sliced in rounds (5 mm)