Ham, leek & mustard tart

Put the flour, butter and salt into a food processor and blitz until the mix resembles breadcrumbs. Combine the egg yolk with 2-3 tbsp cold water, add to the mixture and blitz again until the pastry comes together into a ball (you may need to add more water). Shape into a disc, wrap and chill for 1 hour.

Lightly dust a rolling pin and a large sheet of baking parchment with flour. Roll the pastry out on the parchment, and use it to line a 3cm deep, 23cm loose-bottomed tart tin. Cover and chill for 30 minutes in the freezer or the coldest part of your fridge until firm. Meanwhile, preheat the oven to 200ºC, gas mark 6 and put a baking sheet inside.

For the filling, heat the butter in a heavybottomed frying pan over a medium heat, then add the leeks, stir, season and add 3 tbsp water. Cover, reduce the heat to low and cook for 15 minutes until the leeks are soft. Uncover, increase the heat and cook until any liquid evaporates. If the leeks are ‘wet’ it will spoil the custard filling, making it difficult to set. Remove from the heat and leave to cool.

Prick the base of the pastry case all over with a fork, then line with baking parchment and baking beans. Bake on the hot baking sheet for 12 minutes, then remove the parchment and beans, return to the oven and bake for 13 minutes more. If little cracks appear, fill them with a tiny bit of leftover pastry.

Reduce the oven temperature to 170ºC, gas mark 3. Leave the case to cool, then carefully spread the mustard on the base, followed by the ham and leeks. Mix together the cream, whole egg and egg yolks. Season well. Carefully pour over the leeks and ham, then scatter on the cheese.

Return the tart to the baking sheet in the oven and bake for 40-45 minutes, or until the pastry is golden and the filling is just set in the middle (it will continue to cook as it cools). Leave to cool for 15 minutes (take care, as it’s very hot when it first comes out), then carefully remove the tart from the tin to serve.