To bake hot cross buns, combine water, milk, sugar, yeast and let rise for 30 minutes. Add melted butter, egg yolk, vanilla and flour mixed with spices to the yeast mixture. Knead into an elastic dough and add currants. Shape into rounds and let rise for 1.5 hours. Flatten dough and cut into rounds, place in pan and let rise 40 minutes. Bake at 375°F until golden brown, then glaze with icing sugar mixture and add crosses on top.