Frosted Strawberry Cookie Bars

15.25 oz box strawberry cake mix

1/2 c. butter, very well softened

1 egg

Frosting:

8 oz. cream cheese, softened

1/2 c. butter, salted

1 c. powdered sugar

1/2 t. vanilla or strawberry extract

sprinkles, optional

Preheat oven to 350. Spray 9x13 pan. Combine cake mix, butter, and egg on medium high speed until well combined. Turn dough out into 9x13 pan. Dough will be quite thick. Using fingertips, press dough into pan. It will be on the thin side. Bake for 12 minutes until center is set and toothpick inserted comes out clean with no batter. Allow bars to cool in pan for 1 hour before frosting. 

Make frosting while bars are baking. Combine cream cheese & butter, beating on high speed until fluffy, about 2 minutes. Slowly add powdered sugar and extract. Beat until smooth about 2 minutes. Turn frosting out onto cooled bars and spread until smooth. Add sprinkles, if desired.