Preheat oven to 200°C/390°F. Add dry ingredients to a large bowl and mix together.
Add buttermilk and mix into a dough. Shape the dough into a ball without kneading it at all.
Transfer the shaped dough onto a baking sheet, dust with whole-wheat flour. Use a sharp knife to score the top with a deep cross. Bake for approx. 35 min. at 200°C/390°F.