1. Put the 175g (6oz) flour, spices, lemon zest and yeast into a medium bowl.
2. In a small saucepan, or in the microwave, gently heat the milk and fat together until the fat has melted. Cool until tepid then whisk in the egg yolk.
3. Add to the dry ingredients and mix to a soft dough with your hands. Tip the dough out on to a lightly floured work surface and knead in the sultanas. Lightly knead for 10 minutes until silky and elastic and shape into a smooth ball. (If you prefer, you can do this stage in a food processor with a dough hook.)
4. Lightly oil a bowl and drop in the dough. Cover with cling film and leave to rest in a warm place for about 1½ hours or until doubled in size.
5. Turn the dough out on to a lightly floured surface once more and divide into 4 balls. Line a baking tray with baking paper and place the balls in a tight square and flatten them slightly.
6. Cover with oiled cling film and leave for 30 minutes, or until the buns have doubled in size.
7. Heat the oven to 220C, 200C fan oven, Gas 7. Mix the remaining 25g flour to a thick paste with water. Put into a piping bag or the corner of a small plastic food bag.
8. When the buns have risen, brush lightly with milk and pipe a cross on each one. If using a food bag, snip the corner off the bag to leave a small hole for piping.
9. Bake the buns for about 15 minutes or until pale golden-brown, turning the baking tray round halfway through if they are not cooking evenly. Cool on a wire rack.
- Any dried fruit can be used, such as dried cherries, apricots or figs, but make sure they are chopped into small pieces.
- For a shiny, sticky finish, dissolve 1 tsp caster sugar in 3 tsp of warm water and brush over the cooked buns.