Take Bread dough, or Kuchen dough, and when well risen, toss on floured baking board, roll into a square sheet ¼ inch thick. Spread with melted butter, and cut into 6 inch squares, then cut each square into two equal parts through opposite corners, thus forming two triangles. Roll over and over from the longest side to the opposite corner and then shape the rolls into half moons or crescents. Place in floured or greased pans, rather far apart; brush with beaten yolk to which a little cold water has been added and sprinkle tops of crescents or horns with poppy seed. Set in warm place to rise and when double its bulk, bake in hot oven until brown and crusty.