1. Preheat the oven to 200°C, Gas Mark 6 and put the top shelf in position.
2. Place the flours, bicarbonate of soda and salt into a large bowl and stir together.
3. Make a large hole in the centre of the flour mixture and pour in the melted butter and treacle plus enough of the buttermilk to make a loose sticky dough.
4. The best way with treacle is to run the tablespoon under a really hot tap for 10 seconds before dipping it into the treacle. This ensures the treacle runs easily off the spoon and into the dough.
5. Tip the dough onto a lightly dusted work surface. The dough will be quite sticky. Knead it for 1 minute, then shape it into a large ball with a taut, smooth top.
6. Place the dough on a baking tray and flatten it a bit. The easiest way to do this is with a rolling pin. Take a wooden spoon, put some flour over the whole handle then hold it horizontally over the bread.
7. Put the wooden spoon handle on top of the bread then push it down until you feel the baking tray at the bottom. This mark is the first half of the trademark soda bread cross.
8. Repeat with a line at right angles to this. Dust with some flour then bake in the over for 30-40 minutes, or until the bread is brown, has risen nicely and the dough inside where the cross was made is not damp.
9. Serve fresh from the oven with butter and jam. This bread does not keep well so is best eaten on the day that it is baked; however if you have any left it does make good toast.
Recipe courtesy of Lorraine Pascale, Baking Made Easy HarperCollins, 2012 (£20)