Steak & onion pie
For the pastry
For the filling
To make the pastry, put the butter, egg and yolks in a blender or food processor, and process until pale. Add the flour and salt, and pulse until the mixture just comes together. Add the iced water, process for 1 second, then tip the dough out into a bowl and use your hands to bring together. Divide in two, with one piece slightly larger than the other. Wrap in cling film, and chill for 30 minutes.
Preheat the oven to 200°C/400°F/Gas mark 6.
Roll out the smaller piece of dough into a large rectangle measuring about 23 x 28cm/9 x 11in. Slide the dough onto a greased baking tray. Prick all over with a fork and bake for 10–15 minutes. Cool.
To make the filling, melt the butter in a frying pan, add the leeks and mushrooms and cook for about 10 minutes until soft. Stir in the cheeses and season well with salt and pepper. Spread half of this mixture over the pastry base, leaving a border around the edge. Cover with the ham.
Mix the mustard with the fromage frais, season with salt and pepper, and spread over the ham. Top with the remaining leek and mushroom mixture. Lightly brush the edges with water.
Roll out the remaining dough on a large piece of baking parchment. Carefully place on top of the pie and remove the parchment. Press the dough down to seal. Brush all over with beaten egg.
Bake in the oven for 35 minutes until the pastry is golden and crisp. Serve either hot or cold.