Sourdough Baps

Directions

1. Make the levain (9:00 p.m.)
   
   In the evening, when your sourdough starter is ripe (when you’d typically give it a refreshment), make the levain. In a large-size jar (this levain will rise relatively high, so be sure to give it plenty of headspace), combine 57 grams bread flour, 57 grams water, 23 grams ripe sourdough starter, and 11 grams caster sugar. Cover the jar loosely and let the levain ripen overnight at warm room temperature (I keep mine around 74 to 76°F/23 to 24°C).
2. Mix the dough (9:00 a.m.)
   
   To the bowl of a stand mixer fitted with the dough hook attachment, on low speed, mix the 518 grams flour, 310 grams water, 42 grams caster sugar, 11 grams salt, and the ripe levain until combined and no dry bits of flour remain. Increase the mixer speed to medium-low and mix for 3 to 5 minutes, until the dough clumps around the dough hook. This is a firm dough at this point until we begin to add the oil after a rest.
   
   Let the dough rest for 10 minutes in the mixing bowl, uncovered.
   
   It will take several minutes to mix in all the oil for these baps. Turn the mixer on to low speed and begin to add the vegetable oil, about a teaspoon at a time, while the mixer is running. Patiently add more oil only as the previous addition has been absorbed. While mixing, continue adding all the oil until the dough smooths out and holds together in a cohesive mass.
   
   Transfer the dough to another large bowl or container for bulk fermentation.
3. Bulk ferment the dough (9:30 a.m. to 1:00 p.m.)
   
   Cover the dough with a reusable airtight cover and let it rise at warm room temperature (76°F/24°C) for a total of 3½ hours. During this time, you’ll give the dough three sets of “stretches and folds” (see next step for explanation) to give it additional strength. The first set is performed 30 minutes after the start of bulk fermentation, and subsequent sets at 30-minute intervals, then the dough will rest for the remaining 2 hours. Set a timer for 30 minutes and let the dough rest, covered. After 30 minutes, give the dough its first set of stretches and folds.
   
   For each set of stretches and folds: With wet hands, grab the north side (the side farthest from you) of the dough and stretch it up and over to the south side. Then, in the same way, fold the south side up to the north. Then, perform two more folds, one from east to west, and one west to east.
   
   After performing the three sets of stretches and folds, let the dough rest, covered with the same airtight cover, in the bulk fermentation container for the remainder of bulk fermentation.
4. Shape the dough (1:00 p.m.)
   
   This dough can be proofed on a parchment or silicone-lined full sheet pan (18x26-inches) or two half-sheet pans (13x18-inches). Uncover the bulk fermentation container and lightly flour the top of the dough. Using a bowl scraper, gently scrape the dough out to your work surface. Then, using a bench scraper, divide the dough into eight equal portions (each weighing about 125 grams). Using the bench scraper in one hand, shape each portion into a very tight ball with a seam on the bottom. I like to use my bench scraper at a 45° angle to the work surface to push the dough against the surface, creating tension along the sides and top of the piece of dough. Once shaped, transfer the piece to the prepared sheet pan.
5. Proof the shaped dough (1:30 p.m. to 3:30 p.m.)
   
   Cover the sheet pan with a large reusable piece of plastic or bag and seal shut. Proof the dough at a warm temperature (74 to 76°F/23 to 24°C is ideal) for about 2 hours. The dough is ready to bake when it has puffed up, feels light and airy, and a gentle poke springs back very slowly. If there is any resistance felt in the dough when poked, let it proof for another 15 minutes and check again.
6. Bake the baps (3:30 p.m.)
   
   Position a rack in the middle of the oven; heat the oven to 425°F (220°C).
   Pour the ¼ cup of whole milk (or whisk the egg and 1 tablespoon whole milk) into a small bowl and gather a pastry brush. Additionally, gather a small amount of bread flour and a fine sieve to dust flour on the top of the rounds.
   Once the oven is preheated, use the pastry brush to brush on a thin layer of milk or egg wash onto each round. Then, use the sieve to tap out a light dusting of flour onto the round. Alternatively, skip the wash and simply dust the baps with flour.
   
   Bake for 20 minutes. After 20 minutes, rotate the pan back to front, reduce the oven temperature to 350°F (175°C), and bake for an additional 15 to 20 minutes, until the baps are golden.
   
   Once the baps are baked, remove them from the oven and transfer them to a cooling rack. Let them rest for 30 minutes before slicing.