Cut the butter into cubes and place it in a saucepan along with the soft brown sugar and treacle. Place the pan over a low heat and stir until all the butter and sugar have melted.

Pour the melted mixture into the oats and mix well. Tip the mixture into the lined tin. Spread into an even layer and press it down firmly.

Bake in the centre of the oven for 40-50 minutes, until it’s starting to turn a darker colour around the edges.

Remove the tray bake from the oven and mark it into 12-14 fingers, then leave the flapjack to cool in the tin.

When cold, use the lining paper to lift the flapjack out of the tin and then cut or break along the marked lines.