120g Bread Flour
50g Sourdough Starter
50g Water
—-120g Boiled Water
60g 00 Flour
—-290g 00 Flour
Previous Biga
Previous Tangzhong (hydrated flour paste)
2.0g Dried Yeast
180g Cultured Buttermilk
40g (one large) Egg White
60g Ghee/Cultured Butter
20g Lactose/Sucrose
6.0g Salt
Prepare the biga by combining the bread flour, sourdough starter, and water. This will be a fairly stiff form of pre-ferment, and that is the intention. Let sit covered for anywhere around 8-12 hours at room temperature, or roughly 4 hours at room temperature and up to 24 hours refrigerated.
When the biga is ready, separately measure the first small quantity of 00 flour. Measure the required amount of just boiled water; which is easiest to do with a kettle and by volume in a heatproof measuring vessel (120mL). Relatively quickly, add the 00 flour to the hot water and incorporate thoroughly with a small utensil.
Give the hydrated flour paste just a few minutes to cool down before placing into the work bowl, alongside the biga. This is also a good opportunity to measure all of the remaining ingredients, leaving separated.
Add approximately a third of the remaining 00 flour to the work bowl, before turning the stand mixer to a low speed with the dough hook. Work the current mixture until the flour is mostly absorbed, before stopping the machine and adding the remaining flour and the dried yeast.
Continue to incorporate this flour on a low speed for roughly 2-3 minutes, although it will not be completely absorbed. With the machine still running, slowly add the buttermilk, stopping if you see the liquid actually begin to pool. Continue adding the buttermilk in installments as necessary until everything is in, and just beginning to come together in the bowl.
Once at least a shaggy mass has formed, begin to increase the speed of the stand mixer in increments, until it is relatively high but the machine is stable. Continue to work at this speed for at least 10 minutes.
After this, the dough should look cohesive, smooth, and stretch easily when tested. Either way, add the salt and mix for at least one more minute, although longer if it did not reach the desired appearance just described.
Bring the mixer down to the lowest speed, before adding a small piece of the measured butter. Continue for roughly 1 minute before increasing the speed to medium, until the butter disappears into the dough. Repeat this cycle until all of the butter is incorporated.
Lastly bring the mixer back to the lowest setting, before sprinkling in the lactose/sucrose. Mix until incorporated.
Scrape the dough off of the hook and sides of the bowl, before doing preliminary shaping into a vague ball. Either cover the work bowl with plastic, or transfer to an appropriate vessel that will accommodate up to twice the current volume.
Begin the fermentation at room temperature for anywhere between 1-4 hours, before refrigerating. The cold fermentation can last anywhere between 18-48 hours. The flavor will change slightly from the longer fermentation, but it is best to determine more based on your personal schedule.
Whenever ready to proceed, divide and shape the dough as desired. The exact quantity used will depend on your loaf pan. Extra bread dough (or the entire batch) can be shaped into buns, rolls, or even repurposed for dessert baking.
Allow the shaped dough to proof at room temperature (or a slightly warmed environment of up to 32°C), covered loosely with plastic wrap. Watch closely to approach almost doubled in size by volume, but ultimately determine whether it is ready with a poke test.
If active steam is available, preheat the oven to 200°C (400°F) and 100% steam. Bake initially for 8 minutes, before decreasing the settings to 175°C (350°F) and 0% steam, for an additional 15-20 minutes, checking that the internal temperature reaches at least 90°C (194°F).
For a conventional oven, bake the entire time at 175°C for a full 20-25 minutes, checking to reach the same internal temperature.
Allow the bread to cool completely before removing from the plan and slicing.