Recipe Clarification
The challah recipe I sent out previously was a half recipe, which would only yield 3 challahs and would not require a bracha of "L'hafrish challah". You can blame it on post-Covid brain, but I intended to send out a double recipe that actually does yield 6 large fluffy challahs - my apologies for that. Please follow the recipe below for best results - and feel free to email or text me with questions.
Bracha & Separating
If you make this full recipe with 14+ cups flour, it's enough to be mafrish challah (separate a small piece of dough) and recite the bracha. If you make the half recipe, you can still separate the dough and recite the longer yehi ratzon, but you should not recite the bracha of "L'hafrish challah min haisah".

If you are preparing the full 14 cup recipe but you will be making babka or rugelach out of some of it, you also should not recite the bracha, but you may recite the yehi ratzon. (per Rabbi Dov Foxbrunner)
All-In-One Challah Recipe
by Sarah Faygie Berkowitz

If you don't need 6 challahs, you can use a portion of the dough to make a babka, a pizza dough, babka muffins, rugelach, or calzones. The options are limitless! See storage and usage note below recipe.

YIELD: 6 large challahs
PREP TIME: 1 HOUR
COOK TIME: 30 MINUTES

INGREDIENTS
4 1/2 Tbsp yeast
2 cups warm water
2 Tbsp sugar
14 - 15 cups flour (can be a blend of bread flour or all-purpose flour and whole wheat. I typically use 10 cups all-purpose flour, 4 cups whole wheat)
3 cups warm water
1 cup oil
1 cup sugar
2 Tbsp salt
1 egg, for egg wash
everything seasoning or topping of your choice
DIRECTIONS
  • In a small bowl, combine yeast, 2 cups warm water and tablespoon sugar. Allow to sit for 10 minutes.
  • Meanwhile, mix flour, water, sugar, oil and salt in a large bowl.
  • Add yeast mixture to flour mixture and knead until smooth. You may need to add up to an extra cup of flour if dough is sticky, but try to add as little as needed. Too much flour will affect the fluffiness and taste of the dough.
  • Cover and allow to rise for 30 – 40 minutes.
  • Punch down dough, cover, and allow to rise for another 20 – 30 minutes. (If you're in a hurry you can skip the second rising.)
  • Punch down dough. Divide dough in 6 equal pieces. Divide each piece into six equally-sized pieces, yielding 24 dough balls.
  • Sprinkle counter or work space with flour, and braid your challahs.
  • Place challahs on parchment lined baking sheet. Allow to rise for 20 – 30 minutes.
  • Beat egg with a few drops of water, and using a pastry brush, coat the top and sides completely. Sprinkle with topping of your choice.
  • Bake at 350 for 12 minutes, then reduce oven 20 335 and bake another 20 minutes. Allow to cool on wire racks.

These challahs freeze beautifully! Wait until they are completely cool before bagging. Defrost out of the bag on a paper towel to eliminate any moisture, and reheat briefly before serving (or before candle lighting) for a fresh taste.

Dough Tip: If you don't want to use of all your dough the same day, stick the extra portion or two in gallon ziploc bags and take out of the fridge about an hour before you're ready to roll and bake. The dough will stay good in the refrigerator for a day or two, after that it starts to develop a bit of a yeasty taste.