In a small bowl, dissolve the yeast in the warm milk to make a yeast mixture.
In a large bowl, combine eggs, butter, sugar, salt, spices, yeast mixture and 3 cups flour; beat on medium speed until smooth.
Stir in currants, raisins and enough remaining flour to form a soft, sticky dough.
On a floured surface, knead the dough until it is smooth and elastic (about 6-8 minutes). Place in a greased bowl, turning once to grease the top. Cover and let rise in a warm place until doubled for about 1 hour.
Punch down the dough. On a lightly floured surface, divide and shape the dough into 30 balls. Place 2 inches apart on greased baking sheets. Cover with kitchen towels; let rise in a warm place until doubled for about 30-45 minutes. Meanwhile, preheat the oven to 375°.
Using a knife, carefully cut a cross on top of each bun.
In a small bowl, whisk the egg yolk and water together and brush over the tops of the buns. Bake for 15-20 minutes or until golden brown. Remove from pans to wire racks to cool slightly.
For icing, in a small bowl, combine confectioners' sugar and enough milk to reach desired consistency. Pipe a cross on top of each bun. Serve warm.