Butter two loaf pans (I used one square one - I didn't want to make the loaf in two pieces)
Mix flour, spice, salt, yeast and sugar in a large bowl then make a well in the center.
Mix the butter, milk and egg in a separate bowl and then add to large bowl.
Add the currants and mix well. Turn the mixture to the loaf pan(s).
Leave in a warm place for about 30 minutes to rise. Meanwhile, preheat oven to 400º.
If adding fortune-telling charms: Clean and dry charms thoroughly then wrap tightly in parchment paper. Place wrapped charms evenly throughout loaf so that each person being served a slice will be guaranteed a fortune.
When the dough has doubled in size (it took about an hour for me), bake in oven for about 45 minutes or until the loaf begins to shrink from the sides of pan.
Make a glaze by mixing the castor sugar with 2 tbsp boiling water.
Remove loaf (or loaves) from oven and brush with glaze. Return to the oven for 3 minutes or until the tops become a shiny brown.
Remove from pans and place on wire rack to cool.
Serve with Irish butter while warm.