Measure the flour, sugar, salt and yeast in a large bowl of a stand mixer. In a separate bowl mix the egg yolks and oil them add 1 1/4 (270ml) of the warm water and mix until fully incorporated/
Using the paddle attachment on low speed, mix the dry ingredients.
Add the wet ingredients into the flour mixture and keep mixing until the it is hydrated and looks like a messy dough.If you notice that there is some dry flour that does not incorporate, add 1 Tablespoons of water at a time. Switch the paddle attachment to the dough hook and knead at low speed for about 2 minutes. Until you have a smooth dough that stenches but tears easily.
Place the dough in a large ball (OK to leave in the mixer bowl), apply a thin layer of oil on the dough and cover with plastic wrap. Allow the dough to rest and rise until double in size for 6-10 hours.
Punch the dough to release the air, then divide it into two equal pieces. About 680g each.
Divide each piece into as many pieces as you wish to braid and roll each piece into a long sausage than braid. Repeat with the second half.
Gently place each braided loaf over a large cookie sheet lined with parchment paper and brush with the beaten egg. Sprinkle with teh sesame seeds or poppy seeds (optional)
Place the loaves in a warm spot and allow to rest for the second rise, until double in size. About 4-5 hours.
Bake for 25-30 minutes at 350F. (turn the pans mid bake time) The bread is ready when it is deep golden brown and the inner temperature is 180-190. Or when you insert a large wooden skewers there is no resistance and no moist crumbs.
Remove from the oven and place on a cooling rack.