Make the stiff sweet starter: In a small jar, mix 15 g sourdough starter, 15 g honey, 30 g water, and 60 g bread flour until it forms a ball. Knead outside of the jar to fully incorporate the ingredients. Cover loosely and let ferment at room temperature until morning.
Make the tangzhong: Mix 35 g bread flour and 175 g whole milk in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until thickened and reaches 150°F (65°C). For me, it usually takes 3-5 rounds to finish. Cover and refrigerate until morning.
Day 2 (Morning)
Mix the dough: In stand mixer bowl, combine All of the stiff sweet starter, All of the tangzhong, 225 g cold water, 75 g honey, 25 g avocado oil, 575 g high-protein bread flour, and 12 g salt. Mix on speed 1 (lowest speed) for 1-2 minutes until ingredients come together, then increase to speed 2 (a tiny bit faster) and mix for 10-15 minutes, or until dough reaches a weak windowpane. It takes about 10 minutes in a Bosch and upwards of 15-20 minutes in a KitchenAid, for reference.The dough will feel slightly sticky or tacky after mixing, but it should hold its shape. If the dough doesn't fully come together after a few minutes in the stand mixer, add additional flour in 1 tbsp increments.
Bulk fermentation: Transfer to lightly oiled bowl, cover, and let rise on counter until evening (8-12 hours). At the end of bulk fermentation, the dough should have risen by about 40%, have lots of bubbles, and should be puffy when you tap the surface. (My BF took 11 hours; my home was 73°F/23°C and my dough was 75°F/24°C.) Once it reaches this point, put the bowl in the refrigerator until bedtime to slow down fermentation.
Day 2 (Evening)
Shape the dough: If not using a nonstick bread pan, lightly oil it. Bring dough out of the fridge and turn it onto work surface (use a light dusting of flour to prevent sticking, if needed). Using a rolling pin, roll dough into rectangle slightly narrower than pan width (about 10" wide by 14" long).
Roll up the dough tightly, pinch the seams on each end, and place your dough log seam-side down in bread pan.
Second rise: Cover and let rise on the counter, overnight, until very puffy and the dough is even with the height of the pan rim (approximately 8-12 hours). (My dough was ready after 11.5 hours in a 73°F/23°C environment.)Note: If your home is warmer than about 75°F (24°C), the dough will likely overproof by morning. I advise putting it in the fridge overnight and resuming with the second rise in the morning.
Day 3 (Morning)
Bake: Preheat oven to 350°F (175°C). Bake uncovered 40-45 minutes until internal temperature reaches 200-205°F (93-96°C). If the top of the loaf is getting too dark, cover with foil. Once done, immediately brush hot loaf with 1 tbsp butter. Cool in pan 5-10 minutes, then turn out onto rack. Cool completely before slicing (1-2 hours).
Video
Notes
Flour Options:
Bread flour: Ballerina Farms (14% protein) or King Arthur unbleached (12.7% protein) - no adjustments needed
All-purpose: Costco AP flour - add 25g extra flour to main dough
Canadian options: Arva Mills Daisy flour or Boreal Organic All Purpose (Costco) work perfectly (thanks to follower Amanda Steele for this tip)
No stand mixer: If mixing by hand, the goal is still to achieve a strong dough with at least a weak windowpane – it will just take longer to get there. To avoid sore arms, I suggest mixing your dough initially for 3-4 minutes; then, cover and let rest for 30 minutes. Do a few rounds of stretch and folds, each 30 minutes apart. Using a smaller loaf pan: I created a calculator on the recipe post (right above the recipe card)! Just select your loaf pan size, how many loaves you want to make, and copy the new ingredient list.Tangzhong: You can make the tangzhong up to 2 days in advance; keep in fridge. You can also make the tangzhong on the stovetop if you prefer. Heat over medium heat until the mixture reaches about 150°F and is thick like pudding. Ensure it is fully cooled before adding to dough!Rise times: This dough is extremely forgiving. Don't panic about getting the timing exactly right. The most important thing is that the dough is very aerated and puffy to the touch before baking. That said, the general timing provided is from my recipe testing in a 72-73°F (22-23°C) kitchen. If your kitchen is warmer, everything will happen faster. If your kitchen is colder, it will take longer.Pausing the process: Feel free to put your loaf pan in the fridge to "pause" the process at any time. It will slow down fermentation and rise times. Resume when you're ready by bringing the dough back to room temperature and carrying on with the next step.Alternative timeline: Make starter/tangzhong morning of Day 1, mix dough evening of Day 1, shape morning of Day 2, bake evening of Day 2.