Prepare the levain: Mix 50g flour, 50g water, and 25g starter in a straight sided cup or container to track it’s rise. Cover lightly and let sit in a warm place (about 25C/77F) until it has reached or almost reached double in size, about 4-6 hours.
Autolyse: In a large bowl, mix the water and oil, then add in both flours. Mix well until no more bits of dry flour remain. Cover lightly with a damp towel and let that sit for about an hour. (I usually mix by hand, but you can also use a stand mixer to make the process easier.)
Add Levain: Once the levain is light, bubbly, and near double in size it is ready to use. Pour the levain on top of your dough and mix it into the dough. Once the starter is incorporated, cover and let the dough sit for 10 minutes.
Add salt and yeast: Pour the salt on top of the dough, and then pour in the yeast that has been dissolved in about 1 tsp of water. Mix both into the dough. It is normal if the dough does not remain a ball, continue to mix until everything is incorporated and the dough returns to a smooth ball shape. Cover the bowl, or you can move the dough into a greased straight-sided container to track its growth.
Bulk fermentation: Let the dough sit for about an hour in a warm place (about 25C/77F). The fresh yeast will help it to ferment quickly in about 1 hour. If you are tracking the rise in dough, it should reach 50% it’s size or even 75% its size. If it reaches double its size that’s not a problem, however if it does not reach half its size in that time, let it sit in a warmer place for another 15 minutes and check it again.
Pre-shape: Once the dough has fermented, pour it out onto a lightly floured surface. Using a kitchen scale and bench scraper or sharp spatula, measure out 6 individual pieces (about 120g each), or 8 (about 90g each). Shape them into balls and let them rest on a floured surface. Cover lightly with a towel and let sit for 30 minutes.
Shape: Before shaping, prepare a piece of parchment paper that will fit a baking sheet or will fit your baking stone/steel. Gently move each mollete ball and flatten it lightly without knocking out all of the air. Place it on the parchment paper and continue for all 6 balls. Cover with a dry towel and let ferment for about 30-40 minutes in a warm place (about 25C/77F). The dough is ready to bake when they are light and fluffy and have grown slightly.
Preheat the oven: While the dough proofs, preheat the oven above and below to 220C/425F with the baking stone or baking sheet placed inside on the middle rack, for at least 30 minutes. We also need to add in steam to the oven; I usually place a small oven proof baking pan on the buttom of the oven to preheat with the baking stone.
Bake: When the dough is ready to bake, carefully move the parchment paper directly onto the baking stone or baking sheet, quickly pour water into the oven-proof pan on the bottom of the oven, and change the heat source to BELOW only. Bake for 10 minutes. After 10-12 minutes, carefully remove the pan with water, and continue to bake 3-4 more minutes with the heat source above and below. The idea is to continue cooking without browning too much to have the classic white mollete color. They are done cooking when the internal temperature reaches 90C/190F. Remove from the oven, and let cool on a wire rack at least 30 minutes before cutting.