Ingredients

270g Shipton Mill 'Swiss Dark' flour

80g bread flour

245g water (left standing overnight)

75g ripe starter

8g salt dissolved in 10g water

2 tsps good quality unsweetened cocoa

30g hazelnuts, chopped finely (optional)

Method (kitchen temp: 23°C)

Stir the flours together, add the water and autolyse for 1 hour

Add starter and rest for 90 mins.

Add salt water and rest for 30 mins.

Cut off 60g dough, place it in a separate bowl and work the cocoa into it (I added a splash of water to make this easier). Rest for 30 minutes.

Stretch and fold the main dough and rest for 30 mins.

Spray the work surface lightly with water. Wet your hands and stretch the cocoa dough out thinly into a small sheet of dough. Turn the main dough out on to the work surface. Stretch the dough out thinly into a rectangle, working from the centre outwards. Laminate with the cocoa dough and chopped nuts. Fold 1/3 of the dough and then another 1/3 and roll up. Place in a square high-sided bowl and rest. See Instagram: @marielesterbaker for a video of this part of the process.

During the next 90-120 mins perform 2 coil folds.

Preshape and rest for 20 minutes.

Shape into a batard and place in a lined banneton. Rest until proofed (do the 'poke' test to check this).

Place in fridge and retard for at least 12 hours.

Next Day

Place a lidded iron casserole into your oven and heat for 1 hour at 250°C/480°F/Gas mark 9.

Turn your dough out onto a piece of baking paper. Flour lightly with rice flour. Score the dough using a lame.

Transfer the dough on the baking paper to your casserole, and put 3 ice cubes under the paper. Bake for 25 minutes.

Remove the lid, turn the oven down to 220°C/425°F/Gas mark 7. Bake for a further 15 mins.

Remove from oven and place on a cooling rack. Cool completely before slicing. And then enjoy!