Place levain, water, flour and salt into the Thermomix bowl and knead 30 sec/Interval or dough setting. Leave in the Thermomix bowl for up to an hour. Knead further 1 min/Interval or dough setting. Tip out onto an oiled bread mat and wrap. Keep draft free for up to 6 hours until the dough is soft and pliable.
Without worrying too much about it, give the dough a couple of pull and stretches throughout the proofing time.
When you are ready to prove for the last time, cube the cheese into large chunks. Get the charcoal powder ready.
Using the pull and fold method, work the dough, incorporating both the cheese and the charcoal into the dough. A marbled look with the charcoal is really nice.
Repeat pull and fold until you are happy. Flour a banneton with non gluten flour and form the boule as the video instructs. Place pretty side down into the banneton and cover.
Rise until it has reached the top of the banneton or until you are happy it is ready to bake. Preheat your oven and hopefully a cast iron Dutch oven for at least 30 minutes to an hour at 260°C. When you are ready to bake, turn the banneton upside down onto a piece of baking paper, score the loaf in your pattern of choice and quickly transfer to the Dutch oven, lid on. Turn the oven temperature down to 220°C and bake 20 minutes. Remove lid and bake further 25-30 minutes. It can be difficult to tell if you have achieved the crust you are hoping for with this loaf so your experience and tapping the loaf hoping for a hollow sound will help you.
This crust is a bit more chewy than a regular loaf with no charcoal. It is delicious toasted and that cheese, oh my! Pass the Pepe.