Mix water with dry yeast and sugar and set aside until it becomes foamy (5 – 10 minutes).
In a large bowl mix the flour with the starch and salt. Add the egg, oil and yeast mixture.
Knead by hand or with a dough hook in the stand mixer for 8 – 10 minutes. When the dough is smooth and elastic place it in a lightly greased bowl, cover the bowl with plastic wrap and let it rise in a warm place for 1 hour or until it doubled the volume.
The rising times are approximate, it can take more or less time depending on the temperature of the environment, the freshness of the yeast, the strength of the flour and other factors not related to the recipe.
Deflate the dough. Knead shortly. Divide into 8 pieces and on the lightly floured work surface stretched each piece into long strip. Pour over some sesame seeds and roll on the strip to make the seeds stick to the dough.
Cut the dough with a knife or scissors along the side, forming a 1 cm large fringe pieces.
Roll up the strips (overlaying the stripe on itself in a spiral way). Transfer onto a baking tray lined with parchment paper. Cover with the cotton cloth and allow to puff for half an hour in a warm place. After this time, whisk an egg with a little of water and brush the buns gently with the egg wash.
Bake in a preheated oven at 220° C for about 20 minutes. Let it cool completely on baking rack before serving.