Preheat the oven to 150˚C.
Grease and line with parchment paper an 8inch cake tin.
Place the flours, porridge oat, salt into a large mixing bowl. Sieve in bread soda and combine with the flour mixture.
Make a well and add the egg and treacle. Slowly pour in the buttermilk and stir to combine to get a soft ball but not too sticky. Dust with extra flour and shape into a ball.
Place into a the tin and cut the top of the bread with a knife to create 4 cuts.
Brush the top of the bread with a leftover mixture of buttermilk and drizzle of treacle.
Bake in the oven for 1 hour or until hollow when tapped on the base. Remove from the oven and allow the bread to cool down.
This loaf will keep fresh for 4–5 days and is suitable for freezing.
