To begin you will need to prepare the sourdough three days in advance. On the first day mix 100g of wheat flour with 100ml of water, and leave to stand for 24 hours. If the dough has bubbles, remove half the mixture and replace with the same amount of flour, mixing again. If no bubbles have formed allow to rest for another day.
On day three, whether or not bubbles have formed, again remove half the mixture and replace with the same amount of flour, integrating once more. The sourdough is now ready to prepare pan de mole.
In a mixer, add all the pan de mole ingredients and mix thoroughly. Leave to stand for 30 minutes. Slowly add the water to assist with fermentation, then leave to stand for 20 minutes.
Form the dough into small balls of approximately 50g and place on a waxed paper-lined tray. Add sesame seeds and allow to ferment for 2 hours, or when the dough has doubled in size.
Put the tray into the oven, pre-heated to 200°C. Throw a splash of water onto the oven floor and immediately close the door. Leave to bake for 10 minutes, or until nicely browned.