For the pastry:
350 g plain flour
275 g chilled butter or margarine
a little caster sugar
For the filling:
50 g butter
50 g soft brown sugar
25 g chopped mixed peal
225 g currants
Sift the flour and salt together, and using a coarse grater, grate the butter or margarine straight into the flour and mix it in with a knife so that the butter is coated with flour and not in big clumps.
Stir in just enough cold water to make a soft but not sticky dough. Wrap in greaseproof paper and chill in the fridge for 15 minutes to firm up.
Preheat the oven to 230C/Gas 8.
Meanwhile make the filling by melting the butter and sugar together over a gentle heat.
Stir in the currants and mixed peel.
Roll out half the pastry and use it to line the base and sides of a 20 x 30 cm swiss roll tin.
Spread it evenly with the fruit filling.
Roll out the rest of the pastry to cover the surface, Moisten the edges of the pastry in the tin then lift the top into place and press it firmly to seal the edges.
Score the top into small diamonds or squares, brush with a little water and sprinkle thickly with caster sugar.
Bake in the centre of the oven for 20 minutes then reduce the heat to 200C/Gas 6 for a further 10 – 15 minutes or until the pastry is golden brown and cooked.
Leave in the tin until cold then cut into pieces and serve.