Soda bread is popular in Ireland, where soft wheat grows much better than the gluten-heavy hard wheat.
This soda bread is a simple combination of cultured milk, flour, salt, and soda. A little butter gives the bread added moistness. This recipe can be made with spelt only, but when cut with rye flour it produces a more interesting loaf.
Combine flours in a medium bowl. Cut in butter and drizzle in buttermilk, then mix until completely combined. Cover and place in a warm spot for 12-24 hours.
Preheat oven to 350°F.
Combine salt and baking soda in a small bowl. Sprinkle the mixture over the soaked dough and knead it in for several minutes. Add a bit of flour to keep the dough from sticking, if necessary. Knead until the salt and soda are mixed in and the dough can be formed into a ball.
Place on a greased cookie sheet and cut a ¼-inch X into the top with a sharp knife.
Bake 30-35 minutes, or until the loaf is golden-brown and has reached an internal temperature of 190°F.