Combine 100 grams rye flour with 125 milliliters lukewarm water in a wide-based jam jar. Mix well with a plastic spatula, then cover the top of the jar with a piece of muslin or a clean tea towel and leave somewhere warm for 24 hours.

The next day, combine 75 grams (three ounces) of your mixture with 50 grams rye flour, 50 grams plain flour and 115 milliliters (four and one-fourth fluid ounces) of lukewarm water in a small bowl. Discard the rest of your day one starter and put your new mixture back into your cleaned jar. Cover, and leave for another 24 hours, as before.

Repeat the process every day for a week. You should now notice that your mixture becomes bubbly and elasticated, rising up the sides of your jar. It’s now ready to use! If you are making bread regularly, you should feed it daily; otherwise you can refrigerate your mixture, then bring it to room temperature and feed it for a few days before you want to make a loaf of sourdough.

Combine the starter and flour(s) in a large bowl, then mix in 325 milliliters warm water with your hand until the mixture resembles scraggy porridge. Add a little more water if necessary or if you are happy with a wetter dough. Cover with a clean tea towel and set aside for one hour.

Sprinkle the dough with the salt and poke holes into it with your index finger, then set aside for 15 minutes.

With wet hands, pull the dough up from the far side of the bowl and stretch it over to the near side. Turn the bowl 45 degrees and repeat. By stretching the dough like this, the gluten will begin to develop. Do this eight times (until your bowl has travelled a full circle). Cover and set aside for 20 minutes, then repeat the process three more times. Cover the bowl and leave for three hours.

Tip the dough onto a floured surface (or moistened with water if you’re confident with the handling of the dough), cover with a large, upturned bowl and leave for 30 minutes.

Flour a bread-proving basket or line a bowl with a flour-covered tea towel. Gather up the dough, pulling the corners into the middle to make a tight ball, with the air all trapped inside. Carefully lift, seam-side up, into the basket or bowl and refrigerate overnight.

The next morning, preheat the oven to 220 degrees Celsius fan (475 degrees Fahrenheit/gas 9) for 30 minutes with a lidded casserole dish inside. Cut a piece of baking Gefen Parchment larger than the diameter of the basket or bowl.

Remove the dough from the fridge and turn it out onto the prepared baking parchment. Quickly and carefully remove the casserole from the oven. Slash the top of the sourdough with a small blade or sharp knife, then very carefully use the parchment to transfer the dough into the casserole. Pop the lid on, then bake for 25 minutes.

Remove the lid, then cook for a further 20 minutes, or until the loaf is perfectly golden. Carefully remove the dough from the dish using a spatula and leave to cool on a wire rack.