Preheat oven to 350°F and grease bottom of 13×9-inch pan with cooking spray.
In large bowl, beat sugar cookie mix, cake mix, melted butter, eggs and 1 teaspoon vanilla with electric mixer on low speed 30 seconds.
Spread mixture evenly across the bottom of pan.
Bake 32 to 34 minutes. Cool completely.
In large bowl, beat frosting ingredients together. Spread over cooled bars.
Sprinkle with chocolate sprinkles.
Cut into small pieces and serve!