Preheat the oven to 190°C/375F.
Combine both flours, baking soda, salt in a mixing bowl.
In a small bowl whisk buttermilk with the egg and honey.
Make a well in the centre of the dry ingredients, and then pour in the wet mixture. Start mixing with a wooden spoon until comes together. Alternatively you can mix it in a stand mixer.
Turn out the dough on a flour surface and gently knead until smooth. It shouldn't take longer than 20-30 seconds. Add a little extra flour if you find the dough is too wet and sticky or a bit more buttermilk if it's too dry.
Shape into a ball and put on a floured baking sheet. Sprinkle with more flour and score a cross on it and top with flaky sea salt such as Maldon or your favourite.
Bake in the preheated oven for 40-45 minutes until the bread sounds hollow if you tap on it.