Christmas sausage rolls

Method

1. To make the pastry, put the flour and salt into a large mixing bowl and add half the butter. Using your fingertips, rub the butter into the flour until the mix resembles fine breadcrumbs (or pulse briefly in a food processor).
2. Add the remaining butter, the lemon juice and water and mix together using a metal spoon. You should still be able to see lumps of butter. Use your hands to bring the dough together, wrap in cling film, then chill in the freezer for 10 minutes.
3. Lightly dust a clean work surface with a little flour, then roll out the pastry into a rectangle approximately the size of an A4 sheet of paper.
4. Brush off excess flour from the top and fold the bottom third of the rectangle into the centre, then fold the top third over the first one, as though folding a letter. Roll out the pastry again and repeat the process, then chill it for 15 minutes.
5. Rotate the pastry 90 degrees; repeat the rolling and folding twice more, then put it back in the fridge for 30 minutes.
6. To make the filling, mix the raisins, rum and honey in a bowl and soak for 20 minutes.
7. Put the sausagemeat in a mixing bowl with the chopped ham, mustard, spring onions and chopped sage.
8. Grind the biscuits to powder, either by putting them in a freezer bag and bashing with a rolling pin, or whizzing in a food processor. Drain the raisins and add them to the sausagemeat with the powdered gingernuts. Season and mix well (use your hands).
9. On a floured work surface, roll the pastry into a rough 22cm x 32cm rectangle (a little larger than A4) the thickness of a £1 coin. Cut lengthways into 2 even rectangles.
10. Divide the sausagemeat in half, then form into even sausage shapes the same length as the pastry rectangles.
11. For each one, brush the egg glaze on one pastry edge, then fold the other edge over to enclose the filling. Press the pastry edges together to seal. Brush the pastry with more egg glaze, then chill for 15 minutes. Meanwhile put a baking sheet into the oven and heat to 180°C/160°C fan/gas 4.
12. Cut each sausage log into 6 x 5cm portions (see tip). Brush each roll with more beaten egg and sprinkle with mustard seeds (see Make Ahead). Put the sausage rolls on the hot baking sheet and bake for 30 minutes until golden and crisp.