Minced Beef Pie (British Beef)

Preheat the oven to 200C/400F/Gas 6.
Heat the oil in a deep frying pan and fry the minced meat for 4-5 minutes, breaking it up with a wooden spoon as it browns.
Add the onion and cook for 2-3 minutes, then add the tomato puree and cook for a further 2-3 minutes. Add the flour and cook for a further minute, then add the chopped mushrooms, beef stock or stout and a couple of splashes of Worcestershire sauce. Bring to the boil, then reduce the heat, cover the saucepan and simmer for 20 minutes. Set aside and let cool, then turn the meat mixture into a one-litre tart tin.
Roll out the dough on a floured work surface until it is slightly larger than the pie plate. Gently place the dough onto the plate, pressing firmly on the edges. Trim and then shape the fluted edges.
Cut some leaf shapes from the leftover dough and decorate the top of the cake, gluing them to the dough with the beaten egg yolk.
Make three or four slits in the pastry to allow steam to escape, then brush the tart with the rest of the beaten egg yolk and bake in the oven for 20-25 minutes, or until golden brown.
To serve, cut into wedges.

foods：
2 tablespoons vegetable oil
500 g minced meat
1 onion chopped
1 tablespoon tomato puree
1 ½ tablespoons plain flour
75 g mushrooms
250 ml meat broth
Worcestershire Dash Sauce
400 g shortcrust pastry
1 egg yolks