There is a minhag the Shabbos after Pesach to bake shlissel challah as a segulah for parnassah. The dough presented below is an absolute pleasure to work with, and even if you decide to use it just for challah, you will be extremely pleased with the results. The challos come out light and fluffy and have the taam of Gan Eden! I also give the option of dividing the dough in four and making some sweet (Glazed Cinnamon Danish, Chocolate Swirl Coffee Cake) or savory (Garlic Knots, Onion Board) treats without investing too much extra time. They all freeze well, too. You can take challah with a brachah according to all opinions, as the dough uses over 6 pounds (3 kg) of flour. Thanks, HDG.
Place yeast, warm water, and sugar in the bowl of a mixer. Cover and proof for 15 minutes.
Add the remaining ingredients except for egg wash in order, adding the oil slowly after the 15th cup of flour, until incorporated into the dough.
Add remainder of the flour and knead until a soft dough forms. Continue kneading for 10 minutes. If necessary, add an additional 1/4 cup oil at the very end.
Oil the top of the dough, then cover with a clean dishcloth and let rise in a warm corner of the kitchen for 45 minutes.
Punch dough down, take challah and divide evenly in four. For challah, shape into large challahs and/or small bilkelech and let rise 30–45 minutes. For other ways to use this dough, follow the directions for these sweet (Glazed Cinnamon Danish, Chocolate Swirl Coffee Cake) or savory (Garlic Knots, Onion Board) treats.
Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius), brush challahs with egg wash, and bake 35–40 minutes for challah and 25 minutes for bilkelech.