Preheat oven to 375 degrees.
Spray a black cast-iron skillet with non-stick spray. In a bowl, mix together the flour, baking soda, salt and currants. With a pastry knife, cut in the shortening until small pea-sized balls form. Stir in the buttermilk and spoon the soft batter into the skillet. Cut a deep "X" in the dough and bake until browned on top, about 40 minutes. Turn the bread out onto a plate and serve.
Makes 8 servings.