Smoked ham, leek and mustard pie

Method

1. Put the ham hocks in a large saucepan and cover with cold water. Bring to the boil, skimming any scum that rises to the top. Cut the leek in half where the white meets the green, then chop the green part into 5cm chunks (save the white for later). Once the water is boiling, add the green leek, carrots, onion, peppercorns and thyme. Cover and gently simmer the hocks for 2 hours until the meat is falling off the bone.
2. Meanwhile, make the pastry. Mix the flour and butter together using a stand mixer with a paddle attachment (or your hands) until you can no longer see any pieces of butter – but try not to overwork the mixture too much. Add 2 of the egg yolks, milk and 50ml water and mix until it just comes together into a dough. Divide the dough into 2 pieces – one weighing roughly 350g, the other 200g – then wrap and keep in the fridge for at least 2 hours.
3. Once the ham hocks are tender, strain the stock through a fine sieve into a bowl. Weigh out 400ml of the stock and set aside for later. Wait until the hocks are cool enough to handle, then pick the meat off them, discarding any bone, sinew or fat. Put the picked meat in a large bowl and set aside.
4. Slice the reserved white part of the leek into quarters lengthways, then into 1cm pieces. Cook in 10g of the butter for 5 minutes until softened, then mix into the shredded ham along with the mustard. In the same pan, add the remaining 30g butter and allow to melt. Tip in the flour, then cook gently, stirring regularly, for 10 minutes.
5. Gradually start adding the reserved ham stock to the roux, stirring constantly, until fully incorporated, then add the cream. Pour this sauce into the ham mixture until all the mixture is coated but it’s not swimming in liquid (you may not need all the sauce). Stir in the chopped parsley.
6. Line a 15cm cake tin with baking paper, then pour the ham mixture into it. Flatten the top, then cover with another sheet of paper. Put in the fridge to set and firm up for at least 3 hours, or overnight.
7. Once the pie filling has set, unwrap and roll the smaller piece of pastry out to around 3mm thick. Cut out a 20cm circle, then put it on a baking tray lined with baking paper. Beat the remaining egg yolks, brush the circle with a little egg wash, then roll the large piece of pastry out to the same thickness and cut out a 30cm circle. Reserve any trimmings for decorating the pie (if you like).
8. Put the set disc of pie filling on top of the smaller pastry circle, then put the larger disc on top. Use your hands to mould the pastry around it, then crimp the 2 discs together to seal. Neaten up the edges, decorate the pie however you like, then brush liberally with the remaining egg wash.
9. When ready to cook, heat the oven to 180°C fan/gas 6. Pierce a 1cm hole in the centre of the pie, then make a little funnel out of tin foil and pop it in – this will help the pie cook evenly without leaking and ensure any sauce that bubbles out of the top doesn’t spoil the pastry. Bake the pie for 40 minutes.