Mix: Put the dry ingredients into a mixing bowl. With the beater blade, mix to incorporate. Change to the dough hook and knead for 5 to 10 minutes or until the dough cleans the sides of the bowl.
First rise: Pour oil into a clean bowl, put the dough into it and then rotate it around the bowl, making sure that the oil gets all over the dough and the sides of the bowl. Cover with a tea towel and put into a warm place to let double in size. This will mean 2 hours at 80º or 3 hours at 70º.
Second rise: Punch the dough down and let rise for a further 2 hours at room temperature.
Shape loaf and final rise: On the counter, deflate the largest bubbles from the dough turn its edges under to make a loaf Let sit for 10 minutes to dry. Coat the crevices of a banneton with flour. Sprinkle flour onto the loaf, put rounded side down in the banneton, cover with a cloth and let proof for an hour.
Bake: Preheat your oven with the cast iron skillet for at least half an hour at 450º. When the oven is hot, place a piece of parchment paper over the dough and turn the banneton over onto the hot skillet. Bake for 15 minutes at 450º, then lower the temperature to 400º and bake for a further 40 minutes.