1. Preheat oven to 350°F. In a large bowl, beat cake mix, egg, and 1/3 cup water with an electric mixer on medium speed until a soft dough forms. Stir in raisins.
2. Drop by heaping measuring tablespoonfuls 3 inches apart onto lightly greased cookie sheets.
3. Bake 8 to 10 minutes, or until edges are golden brown and centers seem firm. Let cookies cool 2 minutes on sheets, then remove to racks to cool completely. Store in a tightly covered container. Dust with powdered sugar before serving.