Begin the night before by making a biga with 100gm dark rye flour, 100gm of strong white flour, 3/4 tsp of active dried yeast and 250ml of cold water. I use a plastic pudding basin with close fitting lid and leave it on the kitchen worktop. The next morning add the biga to 250gm of trong white flour, 150gm of wholemeal flour and 200ml of cold water. Knead for ten minutes until the dough comes away cleanly from the bowl and becomes elastic. Knead quickly on a lightly oiled surface with lightly oiled hands and put to rise in a covered bowl for an hour or until doubled in size. Turn on to the oiled surface and gently degas. Scrunch up a large piece of non stick baking by spreading out and then shaping