Cream together margarine, peanut butter, and sugar replacement. Add egg, water, and vanilla; beat until fluffy. Combine flour, baking soda, and baking powder in sifter and sift dry ingredients into creamed mixture. Stir to blend completely. Chill thoroughly, at least 2 hours or overnight. Drop by teaspoonfuls onto lightly greased cookie sheet, 2–3 inches apart. Press flat with the floured bottom of a small glass. Bake at 375 degrees for 12–15 minutes. Yield: 42 cookies.