You will need your basic sourdough starter, and from this make a leaven:
40g mature starter which has been at room temperature for 6 to 24 hours since it's last feeding
30g water at 30 degrees C
15g strong white flour
15g Einkorn flour
mix the ingredients, and leave until it doubles in size. It's now ready to use. This will take around 2 to 4 hours
For the Bread.
150g Einkorn flour
350g strong white bread flour
400g water at 30 degrees C
10g fine sea salt
100g of the leaven (above)
Pour the water into a bowl, add the leaven And dissolve with your fingertips. Add the flour and mix together with your hands. Cover the bowl and let it sit for 1 hour.
Mix in the salt. Pinch the dough to break the gluten structure. Gather the dough and create a basic ball in the bowl. Let it rest for 30 minutes.
With wet hands, fold and pull the dough over itself until you feel it pulling back. Stretching the dough strengthens the gluten structure. Rest for 30 minutes in the bowl covered with a shower cap.
Repeat this process 3 times.
Remove the dough, and on a lightly floured surface, pull and fold the dough, tucking it under itself, create a ball. Leave for 30 minutes.
Carefully, pull the dough into a ball, shaping it in to a round shape, place in a floured baneton and leave covered until it starts to rise a little, about an hour.
Place in a refrigerator and leave for anything up to 36 hours.
Pre heat the oven to 250 degrees C when you're ready to bake With the baking dish, tray or Dutch oven inside. Carefully turn the dough out on to the baking sheet or vessel you're using to bake the bread, and slash with a blade to allow the bread to rise and release steam, cracking open along the slash. Pour some hot water in a tray at the bottom of the oven to create steam, or place the lid on the Dutch oven. Bake for 20 mins at 250. Remove the water tray, or take off the lid of the Dutch oven, reduce temperature to 215 and bake until it's the colour you want, dark is best, and should take another 40 mins or so. Remove and cool on a wire rack.