In a separate container put 200 ml lukewarm water, a pinch of sugar and yeast by adding and 5-6 tbsp flour until a thick porridge. Let the mixture it rise in a warm place. Knead the soft dough 1 egg, remaining flour 1/2 tsp salt, pinch of sugar, about 800 ml lukewarm water, milk and yeast effervescent. Divide the dough into two balls. Roll them as the diameter of the pan. On the first sheet rasim sunflower oil and put the mixture of eggs and yogurt, baking soda and the feta cheese. Leave a little of the mixture spreads. Put the second crust and rotate in the same way as in the first sheet. Take the ends and bend them inwards towards the middle of the tray - formed a ball, turn the ball into the tray and flatten with hands - the entire tray. Leave to rise - before baking smeared with a mixture of yogurt and egg. Bake in preheated oven at 200 ° C