Apple and walnut treacle tart pie

1. For the pastry, whizz the walnuts in a food processor until finely ground; tip onto a plate. Put the flour, butter and a pinch of fine salt in the food processor, then pulse until the mixture resembles breadcrumbs. Add the sugar, ground walnuts, egg yolks and 1 tbsp cold water and pulse again. Bring the dough together with your hands, adding a little more cold water if needed. Take 1 /3 of the dough, shape into a disc and wrap in foil or reusable food wrap. Do the same with the larger piece. Chill for at least 20 minutes.

2. Meanwhile, preheat the oven to 190˚C, gas mark 5. For the apple filling, peel, core and slice the apples and put in a large pan with the sugar and cinnamon. Soften over a low-medium heat, stirring occasionally, for 5 minutes. Stir in the lemon zest, walnuts and flour then take off the heat and cool for 30 minutes.

3. On a floured work surface, roll out the larger piece of pastry to line a pie tin (20-22cm diameter, about 4cm deep), leaving about 2cm overhanging. Fold under the edges and crimp so the rim stands about 1cm above the sides of the dish. Line the crust with foil and fill with baking beans. Bake for 18-20 minutes, then remove the foil and beans, brush the base with egg white and return to the oven for 5-7 minutes, until golden.

4. Meanwhile, in another pan, melt the butter over a low heat, then stir in the golden syrup and treacle and heat through. Stir in the cream, take off the heat and beat in the whole egg, egg yolk, lemon juice and salt. Tip in the breadcrumbs, mix well and set aside. Lay a sheet of baking parchment next to the floured work surface. Roll out the smaller pastry disc to about 24cm diameter. Cut into 14 x 1cm strips and put on the parchment. Tip the treacle mixture into the cooked pastry case and spread out. Layer over the cooled apple mixture.

5. Arrange 7 dough strips in one direction across the top of the pie, spacing equally. Working with 1 strip at a time, arrange 7 more strips in the opposite direction, lifting the strips and weaving over and under to form a lattice (see page 119 for instructions). Gently press the ends of the strips to the edges of the baked bottom crust to seal, then trim. Brush the strips with beaten egg white and sprinkle with extra caster sugar. Bake for 40-45 minutes until golden, covering with foil after 30 minutes. Serve warm, with custard or double cream, if liked.