Place your oven rack in lower part of the oven. Preheat the oven to 375 degrees F. Spray two 8-inch round cake pans with nonstick spray.
In a large bowl, whisk together the dry ingredients (flour, sugar, baking powder, baking soda and salt). Add the butter and cut the butter into the dry ingredients with a pastry blender until crumbly. Stir in the currants. In a separate bowl, beat the egg and buttermilk (and caraway seeds, if using), and stir into the dry ingredients until blended.
Turn the dough onto a floured cutting board and knead until smooth (2 to 3 minutes), adding more flour as needed if the dough is too wet to handle. Divide the dough in half and shape into rounds.
Place the rounds into the prepared pans. Press down slightly and cut crosses on top, 1/2-inch deep.