Preheat oven to 375°F. Combine 1 cup sugar & 3/4 cup butter in large bowl. Beat at medium speed, scraping bowl often, until creamy. Add egg; continue beating until well mixed. Reduce speed to low; add flour, baking powder & salt. Beat until well mixed.
Place remaining 1 cup sugar in small bowl. Shape dough into 1 inch balls. Dip top of each ball in water, then in sugar. Place 2 inches apart onto ungreased cookie sheets.
Bake for 8-14 minutes or until edges are very lightly browned.