Preheat oven to 190°C.
Beat the margarine and Hermesetas Granulated together until light and fluffy. Beat in almost all the egg, reserving a little to use later as glaze, with the lemon rind then add the flour, salt and bicarbonate of soda. Finally stir in currants and mixed peel and mix to make a soft but not sticky dough. Turn the dough onto a lightly floured surface and roll it out thinly. Cut out 7.5 cm fluted rounds then gather up the trimmings, re-roll the dough as before and using the fluted cutter again, cut out more cookies. Brush with beaten egg and bake the biscuits for 8-10 minutes until golden brown. Cool before serving.