01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large mixing bowl, whisk together the flour, baking soda, salt, and sugar until thoroughly blended.
03 - Form a well in the center of the dry ingredients. Pour in most of the buttermilk and mix gently with your hand or wooden spoon until a soft dough forms, adding additional buttermilk only if needed to achieve proper consistency.
04 - Turn the dough onto a lightly floured surface. Knead briefly for approximately 30 seconds just to bring the dough together, being careful not to overwork. Shape into a round loaf about 2 inches thick and transfer to the prepared baking sheet.
05 - Using a sharp knife, cut a deep cross pattern on top of the loaf, extending about halfway through the dough.
06 - Bake for 35 to 40 minutes until the loaf develops a deep golden brown crust and sounds hollow when tapped on the bottom.
07 - Transfer the loaf to a wire rack and let cool for at least 10 minutes. Slice thickly while still warm and serve with generous portions of Irish butter.