Preheat oven to 350 degrees F. Place rack in middle of oven.
Lightly grease a 9-inch cast iron skillet, a 9-inch cake pan, or a baking sheet.
In a large mixing bowl, combine the flour, baking soda, sugar, and salt. Add the butter and cut into the flour mixture with a with a pastry blender or two knives crossing against each other (or you can use your fingers) to mix in the butter until the flour mixture is crumbly in texture.
In a small bowl, combine 1 beaten egg, buttermilk, and raisins, set aside.
Make a well in the center of the flour mixture. Pour the egg mixture into the well. Stir everything together until all the dry ingredients are absorbed.
Turn the dough out onto a lightly-floured surface and gently knead the dough for about 10 to 12 turns until the texture is more elastic and not sticky. You do not want to over handle the dough or it will become tough.
Shape the dough into a round loaf about 6 inches in diameter and place into either cast iron skillet, cake pan, or on a baking sheet. With a sharp knife cut a cross or an "X" on the top surface of the bread loaf (about 1/4-inch deep). Brush the top of the bread with the remaining beaten egg (this will add a nice shiny golden crust).
Place the bread on the middle rack of the oven and bake for 40 to 45 minutes or until the edges are golden brown. A good check is to use an instant digital thermometer to test your bread. The internal temperature of the bread should be at 200 degrees F. when done.
Remove from oven and cool on wire rack for 10 minutes. Slice into wedges and enjoy spread with butter.
Excellent accompaniment to Corned Beef and Cabbage or Guinness Beef Stew - Irish Beef Stew.
Irish soda bread can be wrapped in plastic wrap and stored at room temperature for up to 2 days.
Makes 1 loaf (4 to 6 servings).
* Learn how to make a Buttermilk Substitution.
Irish Soda Bread Recipe: https://whatscookingamerica.net/bread/irish-soda-bread.htm