- Preheat the oven to gas 7, 220ºC fan 200ºC. Grease a 25cm (10in) diameter, shallow pie dish.
- First cook the filling. Heat the oil in a large pan and fry the onion until soft. Cut the gammon and turkey into 3cm (1in) cubes and add to the pan (see Tip below if using leftover meat). Fry for 3-4 mins, then add the leeks. Fry for a further 3-4 mins, then add the flour, stir well and cook for 1 min. Gradually pour on the stock and bring to the boil. Cover and simmer for 10 mins. Add the mustard, taste and season with the pepper if necessary. Ensure the turkey is cooked though, with no pink showing. Remove from the heat and leave until cold.
- Meanwhile, cut the potatoes into chunks and boil for 20 mins until cooked. Drain and mash the potatoes with the milk, cheese and mustard. Boil the cauliflower for about 6 mins until just tender. Drain and add to the mash, breaking it up a little with a fork.
- To make the pastry, put the flour into a bowl and rub in the butter until the mixture resembles breadcrumbs. Add about 2 tbsp cold water and mix to a soft, but not sticky dough. Roll the pastry out on a floured board until large enough to line the pie dish. To line the dish, roll the pastry around the rolling pin and then unroll into the dish, press to fit and trim the edge.
- Spoon the gammon and turkey filling into the pastry case. Top with the cauliflower mash. Bake for 30 mins until golden brown and bubbling. Serve hot.
Tip: If using leftover turkey and gammon, make the vegetable filling in step 2 as above, omitting the turkey and gammon, and leave to cool. When ready to assemble the pie in step 5, stir the leftover cooked turkey and gammon (chopped or roughly shredded) through the cold vegetable sauce then spoon into the pastry case. Top and bake as above, checking that the filling is piping hot before serving.
Freezing and defrosting guidelines
Once the dish has cooled completely, transfer it to an airtight, freezer-safe container, seal and freeze for up to 1-3 months. To serve, defrost thoroughly in the fridge overnight before reheating. Loosely cover with foil and bake until dish is thoroughly heated through. Reheat until piping hot.
Not suitable for freezing if using leftover cooked meat.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.