10:00 PM – Starter Initialization: In a clean glass jar, whisk the 10g of starter culture into 60g of room-temperature water until completely loose. Add the 60g of bread flour and mix thoroughly until no dry spots remain. Cover loosely and let it sit at room temperature 74–78°F (23–26°C) overnight for 8 to 10 hours until the levain bubbles aggressively and at least triples in volume.

8:00 AM – The Grand Autolyse: In your stand mixer bowl, combine all 210g of water, 1 large egg, 80g of granulated sugar, and 112g of your active overnight levain. Whisk briefly to dissolve the sugar, then add all 560g of bread flour (along with the optional 0.5g of dry yeast if using). Mix everything together with a heavy spoon until a very dense, stiff, shaggy mass forms. Cover and let rest for 1 full hour to complete the autolyse and hydrate the flour proteins.

9:00 AM – Primary Gluten Mixing: Secure the bowl onto your stand mixer fitted with the dough hook. Mix the autolysed dough on a low speed for 2 to 3 minutes (or use a KitchenAid mixer on speed 3 for 3 to 4 minutes) until well incorporated. Add the 10g of fine sea salt and continue mixing for an additional 2 minutes until the dough forms a tighter, cohesive ball.

The Slow Oil Emulsification: Turn your mixer up to medium speed and slowly drizzle in the 60g of flavorless neutral oil in a very thin, gradual stream. Once all the oil is introduced, increase the speed and mix continuously for 15 minutes. The dough will look slippery and separated at first but will gradually absorb the oil completely, clearing the sides of the bowl to reveal a smooth, highly elastic surface. *Note: If the dough looks persistently wet or sticky after 12 minutes, add up to 40g of extra bread flour; if it feels like a solid brick, add a small splash of water.*

The Windowpane Verification: Wet your hands with water, pinch a portion of the dough, and stretch it gently upward. It should stretch into a translucent, paper-thin windowpane membrane without tearing, signaling proper gluten formation.

Bulk Proof with Intervals: Cover the container tightly and let it proof for 3 to 4 hours at a warm 76–80°F (24–28°C). During this window, perform 2 gentle rounds of stretches and folds to organize the dough's internal strength. The dough should look visibly smoother and slightly puffy.

1:00 PM – Cold Fermentation Retard: Slide the entire covered container directly into the refrigerator to rest slowly until the next morning. This cools the oils and solidifies the structure, making it much easier to shape.

The Next Morning – Dividing the Portions: Remove the chilled, firm dough directly from your refrigerator. Tip it onto a clean work surface—there is no need to wait for it to warm up, as cold dough is vastly easier to handle. Using a bench scraper and a kitchen scale, divide the dough cleanly into 12 equal portions.

Rope Tension Shaping: Take a portion of dough and pat it into a small rectangle, then roll it up tightly away from you into a cylinder. Roll and stretch the cylinder firmly against the counter using the palms of your hands to form a smooth, uniform rope roughly 9 to 10 inches long. Repeat for all 12 portions.

Braiding the Loaves: Gather 6 ropes together and pinch them securely at the top. Braid them using your preferred method (such as a standard 3-strand or advanced 4/6-strand weave) into a tight, uniform loaf. Tuck the bottom ends cleanly underneath the loaf. Repeat with the remaining 6 ropes to form a second separate loaf.

The Warm Final Proof: Line two separate flat baking sheets with parchment paper. Transfer your shaped challahs carefully onto the trays. Cover them loosely with plastic wrap or a damp kitchen towel. Let the loaves proof for 5 to 6 hours at a warm room temperature of 76–80°F (24–28°C) until they completely double in volume, swelling until the braided strands look extraordinarily light, airy, and soft.

Baking Cycle: Preheat your home oven to 375°F (190°C). In a small bowl, whisk together your egg wash components (1 egg, a splash of water, and a pinch of salt). Using a pastry brush, gently coat the entire surface of your beautifully risen challah loaves with a generous layer of egg wash, ensuring you get cleanly into all the braided creases.

The Deep Golden Finish: Slide the baking sheets onto the center racks of your oven and bake for 40 to 45 minutes without steam. The crust should puff dramatically and turn a uniform, shiny, deep mahogany-golden brown. Transfer the baked loaves onto a wire rack and let them cool completely before tearing or slicing.