Festive eccles cakes

Method

1. For the filling, melt the butter in a medium pan over a low heat. Add the sugars, stir to remove any lumps, then stir in the currants, spices, lemon zest and juice. Stir over a low heat for about 10 minutes until the currants have plumped up a little. Remove from the heat, cover and leave to go cold. As the mixture cools, the fruit will absorb even more of the buttery juices and the rest with solidify around it.
2. For the flaky pastry, cut the butter into 1cm cubes and divide into 4 equal portions. Sift the flour and salt into a mixing bowl, add a quarter of the butter cubes, then rub together until the mixture resembles fine breadcrumbs. Mix the lemon juice into the cold water and gradually add to the bowl, stirring with a round-bladed knife until the mixture comes together in a soft dough. (You might not need to add all the water.) Turn the dough out onto a lightly floured surface and knead gently and briefly until smooth. Roll out the dough into a 20cm x 40 cm rectangle and place so a short edge is facing you. Dot another quarter of the butter pieces evenly over the top of the pastry, leaving a 2.5cm border free around the edge. Fold the bottom third of the pastry up over the middle third, then fold the top third down and seal the edges with the side of your hand. Make a quarter turn to the right, wrap in cling film (keep the pastry in the same position in the fridge) and chill for 20 minutes to relax.
3. Remove the pastry from the fridge, unwrap (keeping in the same position) and roll out once more into a rectangle. Dot with another quarter of the butter and repeat the rolling and folding, including another quarter turn to the right. Chill for 20 minutes again, then repeat to use up all the butter. After another 20 minutes of chilling, roll and fold the pastry without any butter 3-5 times until there is no butter left visible. Chill for 30 minutes before using.
4. Heat the oven 220ºC/200ºC fan/gas 7. On a lightly floured surface, roll out the pastry until 3mm thick, then cut out 8 x 13cm discs using the cutter. Layer the pastry trimmings, re-roll and cut out another 2 discs. Chill for at least 10 minutes. Put a generous tbsp of the spiced filling in the centre of each disc and flatten slightly into a 6-7cm round. Dampen pastry edges with a little water, then draw the edges together over the filling, as if you were making a drawstring purse, to enclose the filling and make a round parcel. Turn each cake over, then flatten lightly with a rolling pin into a 9cm disc, so you can see the shape of the currants through the pastry.
5. Brush the beaten egg white over the tops of the eccles cakes and sprinkle generously with the sparkling sugar crystals/granulated sugar. Make 2-3 small slits in the top of each cake and place seam-side down on a buttered non-stick baking tray. Chill for 10 minutes.
6. Bake for 15-17 minutes until crisp and evenly golden. Cool on the tray for 5 minutes, then cool on a wire rack. Serve warm or cold.