Ingredients:
- 100g Active Sourdough Starter (100% hydration)
- 400g Strong White Bread Flour
- 150ml Whole Milk (lukewarm)
- 50ml Water (lukewarm)
- 50g Unsalted Butter (melted and cooled slightly)
- 10g Fine Sea Salt
- 15g Cane Sugar or Honey (optional)
- 1 Large Egg (whisked for egg wash)
- 1 tsp Water (for egg wash)
- Sesame, Poppy, or Everything Bagel Seeds (for topping)
Instructions:
- Activate the Ingredients: In a large bowl, whisk the lukewarm milk, water, and active sourdough starter together until well combined. Add the flour and sugar (if using). Mix until just combined into a shaggy mass.
- Autolyse: Cover the bowl and let the dough rest for 30 minutes. Then, sprinkle the salt over the dough, followed by the cooled melted butter.
- Knead: Knead the dough (by hand or stand mixer) for 8–12 minutes until it is smooth, elastic, and passes the 'windowpane test'.
- Bulk Fermentation (BF): Place the dough in a lightly oiled bowl, cover, and let ferment for 3–4 hours at room temperature.
- Perform Folds: During the BF, perform 3 sets of stretch-and-folds at 45-minute intervals. The dough should increase in volume by about 30–50% by the end of this phase.
- Divide and Shape: Gently turn the dough out onto a lightly floured surface. Divide into 8 equal pieces (approx. 100g each). Preshape into loose balls and rest for 15 minutes, covered. Then, shape each bun tightly to create surface tension.
- Cold Proofing: Place the shaped buns onto parchment-lined baking sheets. Cover the trays tightly and place them in the refrigerator for 8–12 hours (the cold proof).
- Preheat: Preheat the oven to 200°C (395°F). Place a shallow pan on the bottom rack for creating steam.
- Egg Wash and Topping: Remove the buns from the fridge. Whisk the egg and water together for the wash. Brush the tops of the buns lightly, then sprinkle with seeds.
- Bake: Pour 1/2 cup of hot water into the steam pan immediately after loading the buns into the oven. Bake for 18–20 minutes, rotating the trays halfway through, until deep golden brown.
- Cool: Transfer the Sourdough Buns immediately to a wire rack to cool completely before slicing. This is vital for preserving the crumb structure.