Here's my recipe from Baking Basics and Beyond. I far prefer Irish Soda Bread to green beer to celebrate St. Patrick's Day but a pint of Guiness fits a celebration, too.
Irish Soda Bread
I add golden raisins because their sweetness contrasts with the tangy buttermilk and adds an extra layer of flavor to the bread.
Makes 2 loaves
3 cups all-purpose flour
1 cup whole wheat flour
1/2 cup sugar
1 tablespoon baking powder
1 1/2 teaspoons baking soda
1/2 teaspoon salt
1/2 cup butter, cold, cut into 1/2-inch pieces
1 1/2 cups lowfat buttermilk
1 cup golden raisins
Heat oven to 375°F with oven rack in middle. Lightly grease a large cookie sheet.
Combine flour, whole wheat flour, sugar, baking powder, baking soda, and salt in a large bowl.
Cut in butter with a pastry blender until mixture resembles coarse crumbs with some pea-sized pieces.
Add buttermilk and stir until clumps form, making a sticky dough with ragged edges. Stir in raisins.
Place dough on a well-floured work surface. Dust your hands with flour and knead gently 8 to 10 times or toss dough a few times like a pizza until it just holds together and is no longer sticky. Add a little flour as needed.
Gather dough together and cut roughly in half. Pat each half into a round loaf about 7 inches across. Place both loaves on the cookie sheet. Cut an "X" in the center (to let the fairies out).
Bake 30 to 35 minutes or until deep golden brown with pebbly tops, no longer moist on the surface, but moist inside. Cool loaves on wire cooling racks. Allow loaves to cool at least 10 minutes before slicing.
Baker’s Notes: You can substitute two 9-inch round cake pans for the cookie sheet to help the loaves keep their round shape without changing baking time.
Because this is a sticky dough, you may need to add 1 to 2 tablespoons more flour than in other recipes.
Secrets to Success: You don’t need to mix very much when adding the raisins, as the kneading will distribute them.