Chicken and Leek Pie

Filling

• 450 g chicken stock
• 80 g onions, quartered
• ½ tsp fine sea salt
• 3 black peppercorns
• 1 garlic clove
• 2 sprigs fresh thyme, leaves only
• 1 bay leaf, fresh or dried
• 600 g chicken breasts, sliced (1 cm)
• 200 g leeks, sliced (1 cm)
• 200 g carrots, sliced (1 cm) then halved

White Sauce

• 30 g unsalted butter
• 30 g plain flour
• 250 g milk
• ¼ tsp fine sea salt
• 2 pinches ground black pepper
• 1 tsp Dijon mustard
• 50 g white wine

Pastry Lid

• 375 g puff pastry, ready-made
• 1 egg yolk