Grease a 20cm pie dish, then line with ⅔ of the ready-rolled pastry and set aside in the fridge. Shape the remaining pastry into a ball, wrap in clingfilm and chill.

Heat 1 tbsp oil in a deep frying pan over a medium-high heat. Fry the onions and bicarb for 20 mins or until they’ve formed a deep caramel paste. Transfer to a plate.

Add the remaining 1 tbsp oil to the pan and fry the mince for 5-10 mins, scraping the pan to pick the flavours, until well browned. Return the onions to the pan and add the garlic, tomato purée and Worcestershire sauce. Sprinkle over 1 tbsp flour and cook for 1 min. Stir in the beef stock; simmer for 5 mins to thicken. Season to taste, then set aside to cool to room temperature.

Preheat the oven to gas 7, 220˚C, fan 200˚C and put a baking tray inside to heat up. Roll out the remaining pastry so it’s big enough to cover the top of the pie. Tip ⅔ of the mince mixture into the pastry case, reserving the rest for the Sloppy Joes.

Cover the pie with the pastry sheet, cut away the excess and crimp or seal the edges with a fork. Make a hole in the top with a small knife, then brush with beaten egg. Reduce the oven to gas 6, 200˚C, fan 180˚C and bake on the preheated tray for 35-40 mins until golden and crisp. Leave to cool for 10 mins before serving.