This traditional Irish loaf uses baking soda instead of yeast as its leavener. The advantage is that you don’t have to wait for it to rise or proof, but the resulting loaf will not keep as long and is best eaten the same day. If you can’t find buttermilk, use regular milk instead and add a level teaspoon of cream of tartar.
Sift the dry ingredients into a bowl and make a well in the middle. Reserve 2 tablespoons of the buttermilk and add the rest to the bowl, mixing lightly with a fork as you add it. (Be careful not to overwork the dough, but make sure all the dry ingredients are mixed in. Add the remaining buttermilk if necessary.)
Tip the dough onto a floured work surface and knead gently for 30 seconds to combine. Do not overwork. Line a baking sheet with parchment paper and dust with flour. Form the bread into a round, place on the sheet, and flatten slightly. Use a serrated knife to cut a deep cross in the top of the loaf.
Place in the preheated oven and bake for 30–35 minutes until the soda bread is golden on the outside and cooked through. A good way to check is by tapping the bottom—it should sound hollow when cooked.