Egg whites are separated from the yolks. Whip with a pinch of salt in a thick foam. Grated feta cheese is mixed with flour and baking soda. The yolk is mixed with mustard and three kinds of pepper. Add to the flour and the feta cheese. Once mixed well, add carefully and egg whites. Tray stood greased with butter baking paper. With a teaspoon scoops of the mixture and place on paper. Bake at 190-200C ten minutes until golden. From this dose producing about 20 pretzels.