Add a drizzle of olive oil to a large frying pan and set to a low heat. When the pan is hot, tip in the onions and carrots. Stir occasionally and cook for 5-10 minutes until the onions are soft and have just started to brown a little. Then pop them into the slow cooker.
Add another drizzle of olive oil to the frying pan and tip in the mushrooms. Stir occasionally and cook for 5-10 minutes untill they are tender and brown. Tip them into the slow cooker.
Put the plain flour into a large bowl. Piece by piece lightly dust each chunk of beef and set to one side. When all chunks are dusted turn up the heat to medium and add another drizzle of olive oil to the pan. When the pan is hot tip in the beef and cook until all sides are sealed and have gone brown. Then tip into the slow cooker.
Put the pan back on the heat and pour in the red wine, red wine vingar and Worcestershire sauce. Scrape all the brown sticky bits off the frying pan and allow to bubble for a minute. Then pour into the slow cooker.
Add the potato, bay leaves, finely chopped herbs, fennel seeds, smoked paprika, petits pois and stock to the slow cooker. Add a good pinch of salt and pepper then stir all the ingredients in the slow cooker. Set on low and allow to cook for 6-8 hours (depending on the manufacturers guidance). The mixure will be watery and there may not appear to be much juice, do not be tempted to add more or thicken it up at this stage! Check on it every 1-2 hours and gently stir. Do this more frequentkly towards the end of the cooking time as it may start to stick to the bottom. Add a little water if it does dry out towards the end.
After 6-8 hours the beef should be nice and tender and the gravy should be thicker. Carefuly ladel the contents of the slow cooker into a large bowl or pan to cool completely. At this stage you can refridgerate and make the next day, or continue to make your pies. I refrigerate mine overnight because it tastes better the day after.
When you're ready to make the pies pre heat the oven to 200oC | 180 Fan | Gas mark 6 and remove the pastry from the refriderator. Allow the pastry to stand about 20 minute at room temperature before you unroll it. You will need 6 small dishes, (I use Le Cruset petite round casserole dishes), or a 1 litre rectangular ovenproof pie dish. Unroll the pastry and cut it slightly larger than the pie dish. Carefully drape the pastry over your pie dish and crimp the edges using the back of a fork. Use a sharpe knife to add two little cuts in the centre of your pie and trim off any excess pastry. Crimping holds the ingriedients in place and the cuts allow the steam to escape. Use any left over pastry to decorate your pies.
Wash the tops of your pie with the beaten egg before cooking in the oven for 20-25 minutes for individual pies and 30-35 minutes for a larger pie. Ensure the pastry is golden and the pie is piping hot. Remove from the oven and allow to stand for a few minutes before serving with creamy mash and mushy peas.