Heat oven to 350°F. Spray 8-inch square pan with baking spray with flour.
With lightly floured fingers, break up cookie dough into pan; press evenly in bottom of pan to form crust.
Bake 15 minutes. Remove pan from oven; cool 10 minutes. Meanwhile, in medium bowl, beat cake mix, melted butter and eggs with whisk until well combined.
Spread cake batter evenly over partially baked crust. Return to oven; bake 25 to 30 minutes or until toothpick inserted in center comes out clean. Cool completely, about 45 minutes.
Cut cooled bars into 4 rows by 3 rows; sprinkle with powdered sugar.