Beat sugar, peanut butter, and butter until fluffy. Blend in water, egg and vanilla. Next, add dry ingredients and mix well. Shape the cookie dough into 1" balls. Place them on ungreased cookie sheets. Flatten with the bottom of a glass dipped in sugar. Bake for 8-10 minutes.
While cookies are baking, boil a small saucepan of water. Sit a heat-safe glass bowl on top of the saucepan and melt the chocolate and shortening together. Stir constantly until smooth.
Remove cookies from oven and top each with ½ teaspoon of chocolate. Allow them to cool and set for 10-15 minutes. Enjoy!