In a mixing bowl, combine the flour, salt and caster sugar. Pour the milk into a saucepan and bring to the boil over a high heat, remove from the heat and stir in the butter until melted; allow to cool to 45 degrees C.
Make a well in the centre of the flour and pour in the milk. Sprinkle in the yeast and allow to rest for 2 to 3 minutes until small bubbles appear. Add the egg then bring everything together into a dough using a wooden spoon.
Turn out onto a lightly floured work surface and knead for 5 minutes, stretching and rolling the dough over upon itself to create air pockets until elastic. Place in a lightly oiled bowl, cover with an oiled sheet of cling film to prevent a crust forming then place in a warm area and allow to prove for 1 hour, until doubled in size.
Once proved, add the currants, zest, spices and pearl sugar. Mix well then knead on a lightly floured surface for 5 to 7 minutes until everything is well incorporated. Place back in the oiled boil to prove for a further hour in a warm place.
Form into 12 buns and place on a lightly greased baking tray.
Preheat the oven to 200 C / Gas 6.
For the cross and glaze:
Combine the flour and water to form a thick paste, add a little more or less water to get the consistency right for piping, the mixture should not be runny. Transfer to a piping bag, or small freezer bag with a small hole cut out at the corner then carefully pipe a cross onto each of the buns.
Bake in the preheated oven for 20 to 25 minutes until risen and golden brown. Remove from the oven and transfer to a cooling rack. While still warm, brush with the apricot jam. Serve warm or allow to cool before enjoying.