Beef, Red Wine & Potato Pie - Hanks Meat & Game

Ingredients

• 1kg braising steak, cut into large chunks (shin is a good choice)
• 400ml red wine
• 2 tbsp vegetable oil
• 2 onions, roughly chopped
• 3 carrots, cut into large chunks
• 3 tbsp plain flour
• 1 tbsp tomato ketchup
• 300ml strong beef stock (use 1 stock cube for 300ml)
• small bunch of thyme
• 3 bay leaves
• 3 medium Maris Piper potatoes, finely sliced
• 25g butter, melted
• 625g plain flour, plus extra for dusting
• 1 tsp English mustard powder
• 225g cold butter, diced, plus extra for the dish
• 1 egg yolk, beaten (freeze the white for another recipe)