For the pre-dough (poolish), mix all the ingredients together well and cover the bowl with cling film and leave it to stand overnight (approx. 12 hours) at room temperature.
Dough:
Cut the sun-dried tomatoes into small pieces and mash the boiled potatoes. Mix the flour with the mashed potatoes, add the remaining ingredients and the pre-dough and knead well. If necessary, adjust the amount of flour or water a little (it depends on the water content of the potatoes).
Cover the dough and let it rise for about 1 hour until the volume has doubled.
Then take the dough out of the bowl and divide it into 3 parts for 3 larger baguettes or 5 parts for 5 small baguettes, and shape each into baguettes. Place this on the baking sheet and cover it for another 1 - 1 1/2 hours.
Preheat the oven in time to 220 degrees. Pour the baguettes in well and bake for 30-35 minutes (the small baguettes about 25 minutes).