Not only does slashing a loaf look attractive, it helps the dough to expand on baking. It needs to be done with a confident hand and a very sharp knife or razor blade. Hold the knife at a 45-degree angle to the surface of the dough, and don’t press down but draw the blade across the dough instead. Loaves can be slashed prior to the second rise or just before baking. The earlier it’s done then the wider the split will be. Just remember: super sharp and a swift, smooth, confident action. Flour the top of a loaf before slashing for more distinctive changes in appearance.