Put the sourdough starter in the mixing bowl and add the 50ml water. Use a dough whisk (or fork) to mix the starter into the water. Add the rye and white flour and mix with a baker's whisk. Cover with a cloth and leave for 4 hours.

Salt: Sprinkle the salt on the surface of the dough and with your hand wet with cold water, squeeze your hand through the dough 4 times. Leave covered for 1 hour.

Stretch and fold: Again with wet hands, pull the dough from underneath, stretching and folding over the top. Turn the bowl 180º and repeat. Turn the bowl another quarter of a turn and repeat the stretching of the dough from underneath to top, and finally turn the bowl 180º and repeat. This tightens the dough and you will feel the dough become more difficult to stretch. You may choose to turn and stretch twice more depending on the feel of the dough. Leave covered for 1 hour.

Repeat this stretching and folding each hour, 2 more times.

The Autolyse: Add the water and mix the leaven with the dough whisk. Add the flour and then mix with stand mixer fitted with the dough hook for 5 minutes, first slowly for 2 minutes and then at medium speed for 3 minutes. Cover the bowl wih cloth and leave to rest for 1 hour.

Salting: Sprinkle the salt on the surface of the dough and mix with dough hook for 8 minutes.

Proofing: Transfer the dough to an oiled bowl or round plastic tub with a lid. The bowl should be large enough to allow expandion of up to 2 1/2 times the volume of the original dough. Cover the bowl with cloth and allow to rise for 1 or 2 hours.

Empty the dough onto a floured surface. Rye flour is best for this. Shape the dough roughly into a ball. From the side furthest away from you, pull the bottom of the dough on to the top. Then from the nearest side to you, similarly pull the dough from the bottom to the top. Then do the same from the left and right.

In the morning, take the dough out of the fridge.

Heat the oven to 200ºC with the cloche inside. Leave the cloche heat up thoroughly - at least 20 minutes from when the oven has reached temperature

Take the cloche out of the oven, remove the lid and tip the dough, by quickly turning the banneton up side down into the base of the cloche.

Use a lame to slash your desired pattern into the surface of the dough and replace the cloche lid and return to the oven.