This recipe is from "The Art of Irish Cooking," by Monica Sheridan (Doubleday).
4 cups stone-ground whole-wheat flour
2 cups white flour
1 teaspoons salt
1 teaspoons baking soda
2 cups buttermilk, sour milk or sweet milk
Mix the whole-wheat flour thoroughly with the white flour, salt and soda. Make a well in the center and gradually mix in the liquid. Stir with a wooden spoon. You may need less, or more, liquid -- a lot depends on the absorbent quality of the flour. The dough should be soft but manageable. Knead the dough into a ball in the mixing bowl with your floured hands. Put it on a lightly floured baking sheet and with the palm of your hand flatten out in a circle that is 1½ inches thick. With a knife dipped in flour make a cross through the center of the bread so that it will easily break in quarters when it is baked.
Bake at 425 degrees for 25 minutes, reduce the heat to 350 and bake a 15 minutes more.
If the crust seems too hard, wrap the baked cake in a damp tea cloth and leave standing upright until it is cool.
The bread should not be cut until it has set -- about six hours after it comes out of the oven.