Preheat the oven to 180 degrees Celsius.
Grease and flour a loaf tin.
Combine the flours, baking powder, sea salt and walnuts and set aside.
Mix the bananas, yoghurt, honey, eggs oil and vanilla together.
Fold the wet ingredients through the dry until combined, but don't over stir.
Pour the batter into the loaf tin and bake for approx 55 minutes until the loaf is golden and the cake comes away clean from the sides.
Set aside to cool.
Stores for up to 4 days refrigerated.