Cornish Pasties

Ingredients

• 340 g (2¼ cups) plain flour
• 115 g (¾ cup) strong plain flour
• Generous pinch of salt
• 115 g chilled margarine, cut into small pieces
• 300 ml cold water
• 115 g lard, softened but not melted (see Note)
• 1 egg
• 50 ml milk
• 1 medium potato, peeled and chopped
• ½ swede, peeled and chopped
• 2 onions, chopped
• 1 leek, pale part only, chopped
• 280 g beef skirt steak, diced
• 2 pinches of salt
• ½ tsp ground white pepper
• 1 small knob of butter