Pour water into a large bowl, add dry yeast, salt, and sugar;

Pour in vegetable oil.

Sift about 800 grams of flour into the bowl with the liquid and start mixing with a spoon. Once all the ingredients are mixed, knead the dough with your hands. This will take about 5-10 minutes. The dough should start to come off the bowl.

Dust your work surface with flour and continue kneading the dough with both hands.

Return the kneaded dough to the bowl, cover with a towel or wrap in cling film, and leave in a warm kitchen for 1.5 hours to rise. The dough should double in size.

Place the risen dough back on a floured work surface, sprinkle with flour, and form into challah strands. Make as many strands and as many challahs as you like. Braid the challah strands any way you like. Mix the egg yolk with a tablespoon of water and brush the challah well. You can sprinkle the challah with sesame seeds, poppy seeds, salt, or nut crumbs.

Preheat the oven to 180 degrees and place your challahs there for 20-25 minutes.