There are many different types of this flat bread. This version should remain soft rather than crisp (hence the name lefser, or soft cake). Preheat Oven To 450F. In a large bowl, combine water, butter, salt, rye flour and all-purpose flour and beat well. Stir in whole wheat flour and beat until you have a smooth dough that resembles dough for a baking powder biscuit. Divide dough into 4 parts. Cut each portion into quarters. Flour a board and roll each piece of dough to make a thin 10- to 12-inch circle. If desired, use lefser rolling pin to make a pattern on the dough. Place 2 or 3 dough circles on ungreased baking sheet. Bake in preheated oven 3 to 5 minutes-Not until completely browned. Cool on a rack. Wrap airtight.