Sift flour, baking soda, and salt into a large bowl.
Make a well and pour in milk kefir.
Mix and knead for a few minutes. Add additional flour or kefir as needed.
Shape the dough into a disc and place it on a baking sheet lined with parchment paper. Use a pastry cutter to make a deep cross on the disc. Alternatively, divide the dough into 4 pieces and form triangles. Flatten them slightly and use a knife to draw a cross on each one.
Bake for 45 to 50 minutes until the centre of the dough is well cooked.
Let your soda bread cool and enjoy it on St. Patrick's Day with butter, jam, and a nice Irish tea!