1: If possible, toast 150 g peanuts: put them on a baking sheet in the oven at 300°F (150°C) for 15 minutes. This is not essential, but brings out their full flavour. Leave to cool, then chop coarsely with a knife.
2: Put into a food-processor bowl: 250 g flour, 125 g water, 4.5 g salt, 10 g yeast, 100 g leaven (optional) and 125 g peanut butter.