Preheat your oven to 425°F (220°C) and grease a baking sheet.
In a large bowl, mix the flour, baking soda, and salt together.
Make a well in the center and gradually add enough buttermilk to make a soft dough.
Turn the dough out onto a floured surface and knead lightly.
Shape into a round about 1 1/2 inches thick and place on the prepared baking sheet.
Cut a deep cross in the top using a sharp knife.
Bake in the preheated oven for 25 minutes or until golden brown.
Cool on a wire rack before slicing.