Part One - The Filling
1. In a large bowl, season the flour with salt and pepper before adding in the cubes of steak and mixing thoroughly.
2. Melt the butter and oil in a flameproof casserole dish. Batch by batch, brown the meat for 1 minute at a time and set aside on a plate once done.
3. Fry the onions, leeks and carrots for 2 minutes, before adding the meat back in the pan. Season to taste, then add in the tomato puree, Worcestershire sauce, beef stock and Guinness.
4. Bring to boil, cover and cook at a low heat for around 2 hours until you have a deliciously thick sauce and tender meat. Take off the heat and put filling in a pie dish to cool.
Part Two - The Crust
1. Preheat your oven to 200°C/400°F. Use your fingers to combine the flour, salt and butter until it resembles bread crumbs. Add in the cold water and combine until dough forms. Wrap in cling film and chill for 30 minutes before rolling.
2. Roll out pastry to 3mm thickness and cut a 2cm strip and place aside. Once the filling has cooled, brush water on one side of the pastry strip and press around the rim of the pie dish. Place a pie funnel in the centre to prevent a soggy crust.
3. Cover the top with pastry, making it 1 inch bigger than the dish itself. Seal the pie edges by pressing them down with a fork or your fingers. Brush with beaten egg and make a hole to reveal the pie funnel.
4. Decorate as you like, then bake for 30-40 minutes until it's perfectly golden. Serve with baby potatoes, savoy cabbage and enjoy with a pint of Guinness.