Mixture
In a bowl, add the dry yeast powder, the warm water and the wheat flour, mix very well until combined.
Cover the bowl with a cloth and let it rest for 30 minutes or until it doubles in size.
After this indicated time, add another 200ml of warm water, 3 cups of wheat flour and salt, mix very well until a dough is formed.
Cover the bowl again with a cloth or plastic wrap and let it rest for another 30 minutes.
Sprinkle some flour on the table, place the dough on it after it has doubled in size, then sprinkle some flour over the dough as well.
Shape this dough into a ball and with a spatula or knife, split this dough in half, into equal-sized pieces. Shape these 2 pieces into balls.
Get one of the dough halves and stretch it by hand a bit, do this to both dough pieces (repeat the process described in the video)
Transfer these dough pieces to a baking sheet lined with parchment paper with a split in the middle, or to a baking sheet greased with butter and flour.
For the mixture, into a bowl, add the wheat flour and the cold water, mix well. Add the hot water and mix again until combined. Add the egg yolk and mix.
Brush this mixture over the dough pieces.
With your fingertips, shape these dough pieces as you wish, you can make some lines on their surface and form squares.
Sprinkle some sesame seeds all over it, but that's totally optional and to taste.
Bake in a preheated oven at 200°C (392°F) for 20 to 30 minutes.
Serve.