Preheat the oven to 180°c/Gas 4.
Heat some oil in a large frying pan and fry the bacon and onions until lightly golden.
Add the garlic paste and stir for 1-2mins, empty into a casserole dish.
Add the steak to the pan and fry until browned all over, transfer the beef to the casserole dish.
Add half the ale to the pan to deglaze, add the remaining ale, stock, tomato puree, thyme and bay leaves. Bring to a boil and then pour into the casserole dish, cover and cook in the oven for 1½-2hrs. If after an hour it looks like the juices are drying up, add a little water.
Stir in the cornflour and season, return to the oven for a further 5 mins for the juices to thicken up.
Place a pie funnel (or a rankin dish) in the centre of a pie dish. Pour the beef mixture around the funnel.
Roll out the puff pastry, lay over the top, brush with egg and return to the oven for a further 30 - 35mins until the puff pastry has puffed up and golden.
Serve with mash and veg or chips and extra gravy.