Preheat oven to 400 F line a baking tray with parchment paper and sprinkle a bit of all purpose flour on the top.

In a large bowl, mix flours, salt and soda. Make a well in the centre and pour in half buttermilk (or buttermilk substitute). Using your fingers or a spoon, draw the flour into the buttermilk. Continue to add the buttermilk and mixing the flour in until you have a sticky dough.

Tip the dough out onto a lightly floured surface, shape it into a ball and transfer onto the baking tray. Flatten the dough gently with a palm of your hand and, using a large knife, cut half way through the thickness of the dough to create 4 distinct quarters in the loaf.

Dust the dough with the flour and bake for 30 minutes or until the loaf is golden brown and sounds hollow. Leave to cool on a wire rack.