Preheat oven to 350°F and spray a half hotel pan with cooking spray or coat with butter.
In large bowl, mix melted butter, brown sugar, and Cheerwine Syrup. Add in eggs and vanilla, then whisk until smooth. Add flour, baking powder, and salt, and stir until incorporated.
Pour batter into the prepared pan and smooth out. Bake for 30 minutes or until edges are golden. Allow to cool completely (about 30 minutes in refrigerator). Cut into squares.
In medium bowl, mix store-bought butter cream with 1 cup Cheerwine. Top cooled blondies with prepared butter cream and garnish with powdered sugar and sugar sprinkles, if desired.