1. Combine 200 grams of active sourdough starter with 275 grams of warm water in the bowl of a stand mixer. Use a fork to lightly mix and let the sourdough starter start to dissolve.
2. Next, add 100 grams of white sugar, 4 eggs, 80 grams of oil and 12 grams of salt to the bowl. Mix using the paddle attachment until everything is well combined- about 1 minute.
3. Change stand mixer attachment to the dough hook. Turn the mixer on to 1 or 2 and gradually add in the bread flour, mixing on low speed until a shaggy dough forms. Start with 950 grams of flour and allow the dough to knead in the mixer for 5-10 minutes. If the dough is still sticking to the bottom and sides and not forming around the dough hook, add a little extra flour one tablespoon at a time. The dough should be slightly sticky but workable.
4. Turn the dough out onto a well floured countertop and begin kneading with your palms. The dough may be sticky at first but as you continue kneading it should begin to smooth out. Knead for about 5-10 minutes. Avoid adding extra flour to the countertop unless the dough is impossible to knead/sticking to the counters and not smoothing out. The dough should look smooth and elastic and pass the windowpane test.
5. Transfer the dough to a lightly oiled bowl, cover it with plastic wrap, and let it rise at room temperature for 4-6 hours, or until almost doubled in size.
6. Cover the bowl with plastic wrap and place in the refrigerator for 8-10 hours or overnight.
7. After the cold-proof, remove the dough from the refrigerator and place on a lightly floured surface. The dough should be cold and easy to handle at this point without much flour. Using a sharp knife or bench scraper, separate the dough into 6 equal sections. I like to use a digital scale to ensure each section of dough is equal. Roll each section into a ball and cover with oiled plastic wrap. Let the dough rest for about 10 minutes.
8. Roll each ball into a rectangle about 8 inches long and 4 inches wide. You may need a small amount of flour to keep the dough from sticking. Roll each rectangle up very tightly into a roulade shape. (Similar to rolling up cinnamon rolls.) Roll tightly to avoid air bubbles and pinch to seal. Let each roll rest for a few minutes.
9. Next, between your palms or using the countertop, roll each section of dough into a long cylindrical strip, about 20″ long. Make sure the dough is smooth and even all the way down.
10. I’ve included video directions for both a 4 strand and a 6 strands challah. I recommend watching the video for this part because writing instructions is a bit difficult for the process. I’ve attempted to break down the 6 strand process below:

Braiding Instructions:

1. Start by gently pinching all the strands together at the top
2. Next take the far left strand and cross it all the way over.
3. Take the far right strand and cross it over the opposite way.
4. Now, you should have 2 strands criss-crossed at the top and then 4 strands below. I like to separate the strands into 2 groups. We’ll call them the left side group and the right side group. Slightly separate each group so you have a space in the middle.
5. Take the far left strand and bring it down to the open space in the middle and slightly to the right.
6. Now you’ll notice, the left side only has 2 strands while the right side now has 4.
7. Take the second from the furthest right side strand and bring it all the way across to the left side.
8. You should be back where you started: A criss-cross at the top, and 2 groups with an empty space in the middle.
9. Next, bring the outer most right strand down to the middle. This process continues until the whole loaf is braided.
10. Finally when you have reached the end, gently tuck the ends of the dough under and pinch so the dough forms a nice smooth end. Do the same on the top part of the loaf.

Baking Instructions:

1. Transfer your bread to a parchment-lined baking sheet and lightly cover with oiled plastic wrap. Let the bread rise for about 4 hours at room temp or until it is puffy and jiggly.
2. Preheat oven to 375 degrees F. Mix one egg yolk with 1 TBS of water. Using a pastry brush, lightly brush egg wash all over the loaf. This is what gives the bread that nice shiny, brown finish. Sprinkle sesame seeds or poppy seeds on top for added flavor and texture if desired. Place the loaf in the oven and bake for 35-45 minutes or until it turns golden brown and sounds hollow when tapped on the bottom.
3. Remove the bread to a cooling rack and let it completely cool before digging in. Enjoy this bread with butter, jam, and honey or use it to make the world’s best French toast!