Fry the beef in batches until browned, then add the onions and fry until soft.
Add the beef and onions to a saucepan with the stock, ale, tomato puree, salt, pepper, and bay leaf. Simmer for at least 1 hour until the beef is tender.
Thicken the filling with cornflour mixed with water.
Make the hot water crust pastry by melting the lard/fat and butter in hot water, then mixing into the flour and salt.
Divide the pastry into 3 pieces, wrap in cling film and chill for at least 1 hour.
Roll out the pastry to line 4 individual 5-inch pie tins.
Fill the pastry cases with the cooled beef filling.
Top with the pastry lids, crimp the edges, and cut vents in the top.
Brush the pies with egg wash.
Bake at 170°C for 50 minutes until golden brown.
Allow to cool for 10 minutes before serving.
