First, mix the sugar, salt, cinnamon, flour and baking powder thoroughly in a bowl. In another container, stir the milk with the cooled, liquid butter and the egg until frothy. Then stir the milk mixture briefly into the dry ingredients and finally fold in the currants. Spread the batter in a muffin tin lined with paper liners.
Put in the hot oven and bake on the middle rack for about 20 to 25 minutes.