Prepare the sourdough from ingredients 1-3 and let it mature for 15-18 hours.
For the main dough, knead all the ingredients, including the sourdough, for 10 minutes to create a moist dough. Then let it rest covered for 30 minutes.
Grease a loaf pan, pour in the batter and let it cook for 60-70 minutes.
Preheat the oven to 230 ° C. Pierce the dough several times with a kebab skewer and then bake for 60 minutes. After baking for 20 minutes, turn the oven down to 190 ° C.