Activate the yeast with 1 tsp sugar, the warm water (not hot, pleasantly warm) and several spoons of flour. Stir and leave to effervesce.
Pour part of the flour in a large bowl, add the salt, egg, yoghurt, oil and baking soda extinguished in the vinegar. Once the yeast is ready, add it too. Stir and start to gradually add the remaining flour.
Every flour absorbs differently, so keep adding until you obtain a soft and stretchy dough. It needs to be as soft as the fleshy part of your ear. Leave it to rise until doubled in volume.
Then shape the pita like a turkey. First form the body, then the legs, neck and wings. Leave it to rest for 20 min., smear with the yolk and bake in a preheated 356°F (180 °C) oven.