Preheat oven to 375°F. Combine cake mix, egg, oil, and water in Classic Batter Bowl; stir with Mix 'N Scraper® until thoroughly combined. Mixture will be slightly dry.
Chop nuts with Food Chopper. Transfer nuts to Batter Bowl using Handy Scraper; mix well. Using Small Scoop drop level scoops of dough 2 inches apart onto flat Baking Stone.
Bake 13 minutes or until light golden brown. Cool 3 minutes on Baking Stone; remove to Stackable Cooling Rack. Repeat with remaining dough. Cool completely. Fill Flour/Sugar Shaker with powdered sugar. Sprinkle cookies with powdered sugar.