With a fork beat up egg, salt, add water and flour, beat until smooth. Grease a frying-pan very slightly with butter or oil, pour in two tablespoons of the batter, tilting the pan so as to allow the batter to run all over the pan. Fry over a low heat on one side only, turn out the semi-cooked cakes on a clean cloth with the uncooked side uppermost; let cool. Prepare a filling as for cheese kreplich, using potcheese, butter, add egg, salt, a little cinnamon and sugar to taste and grated peel of a lemon. Spread this mixture on the cooled dough, fold over and tuck the edges in well. Then sprinkle with powdered sugar and cinnamon, and fry in plenty of oil or butter. These blintzes are served hot.