Heat oven to 350°F. Spray bottom and sides of 13x9-inch pan with cooking spray.
In large bowl, mix cookie mix, butter and egg with spoon until soft dough forms. Stir in butterscotch chips and white vanilla baking chips. Using floured fingers, evenly press dough in pan.
Bake 18 to 22 minutes or until toothpick inserted in center comes out clean. Cool completely on cooling rack, about 1 hour. Cut into 6 rows by 4 rows. Store in airtight container at room temperature.