This is my go to challah recipe. Since you are using a 5 lb bag you will be able to perform the mitzvah (commandment) of challah with a bracha (blessing). You will end up with about 6 loaves of challah. You can just freeze any of the challah that you don't use right away.
2 packs of active dry yeast (I really like Fleishmann's)
4 cups of warm water
3/4 cups plus 1 teaspoon of sugar
6 eggs plus 1 egg for glazing
1 tablespoon plus 1 1/2 teaspoons of salt
1 cup of canola oil plus a little extra to oil the dough
1 5lb bag of all purpose or bread flour plus 1 cup on hand during kneading
1. Combine warm water, 1 teaspoon of sugar and 2 packs of yeast. Lightly beat with a whisk (or fork) and wait about 10 minutes until it froths.
2. In a very, very large bowl (I actually use a dish pan) lightly beat the eggs and then add the sugar, oil, and salt and mix to combine.
3. Add the frothy yeast to the large bowl and mix to combine.
4. Add the 5 lb bag of flour and mix with a big spoon until it becomes too difficult to mix.
5. Begin to knead the dough. It will be very sticky. When the flour and water are combined sprinkle a very little bit of flour on it and kneed until it in to the dough. Keep adding flour until the dough is still slightly sticky but not so sticky that it sticks to your hands in pieces. You will have better success with slightly sticky dough than slightly dry dough.
6. Now knead the dough until it is smooth and the dough springs back after you make an indentation with your finger.
7. Roll the dough into a large ball and smooth a little canola oil all over it. Put it back in the bowl and cover the bowl with a kitchen towel. Let the dough rise until it has doubled in size. This will take an hour or more depending on how warm your kitchen is.
8. When the dough has doubled take the dough out of the bowl and punch it down.
9. Shape the dough in to loaves or rolls and let them rise until they double in size again. If you want to make round challahs for the holiday here's an easy way to do it. When you roll out the dough to coil make one end much thicker than the other end. Start the inner part of the coil with the thickest end and just coil it around. Don't forget to tuck and pinch the thin end when you are done so it does not unravel when baking.
10. When the dough has doubled (it will take at least an hour), glaze the loaves with a beaten egg and pastry brush.
11. Bake in a preheated 350 degree oven until loaves are golden. This will take anywhere from 18 to 30 minutes depending on their size. For example when I make a round challah that is 1 1/2 pounds (I weigh the dough on a kitchen scale) I bake it for about 27 minutes. Rolls will take about 18 minutes.