Stir the yeast and sugar into the milk. Allow to sit for 3-5 minutes (maybe more) until to start to see it bubble.
To a mixing bowl add the flour, salt and spices and currants, mix well. Make a well in the center, add the milk and yeast, butter, and beaten eggs. Use a spatula to bring the dough together, then use your hands to make the dough to a large ball. It will be sticky. Turn the dough out on to a floured surface and knead for about 5 minutes, until smooth and elastic. Place in an oiled bowl, cover with a towel and leave in a warm place for about 45 mins to rise. The oven turned off is a good place.
Turn out dough onto a floured surface and knead lightly for a few minutes.
Divide the dough into 12 balls and shape each into a bun. Place close together on baking sheet covered with parchment paper, and cover loosely with a towel. Leave in a warm place for 30 minutes until doubled in size.
Preheat oven to 400°F /200°C.
Mix the 1/3 cup flour and sugar and 3-4 tablespoons of water to form a paste.
Add to a ziptop bag, remove the air and seal. Cut a little off the corner off the ziptop bag and pipe a cross on top of each bun. No need to score the dough, the crosses melt into the the buns as they bake.
Bake for 15-20 minutes until golden brown (time will depend on your oven).
Add the powdered sugar to a small bowl with 1 tablespoon warm water and stir until syrupy. Remove the buns from the oven and brush with the glaze while still warm. Cool on a wire rack.
To store the buns, keep in an air tight container for up to 4 days. If you find the buns getting too firm, I like to microwave them (one at a time) for about 20 seconds, this will soften them up and also make them nice and warm.