Cream together butter and sugar until light and fluffy. Stir in rye flour, all-purpose flour, baking powder and salt. Mix well and add enough water to moisten dough.
Roll out onto floured board. The thinner the dough, the crispier the cookies will be. Cut into 2 1/2 inch rounds using cutter or floured glass. Cut small hole off center with a thimble (to hang on tree when done).
Bake on ungreased cookie sheet at 375 degrees F (190 degrees C) or until slightly brown. Cool and hang on tree with ribbon or yarn.
