Preheat oven to 350 degrees. Line 8x8 metal baking pan with aluminum foil and coat with cooking spray.
Sift flour, baking soda, salt and cocoa together. Set aside.
Set aside 9 junior mints in a small bowl. Put the rest in a medium microwave-safe mixing bowl with 1/4 cup butter. Heat in microwave for 30 seconds. Stir together.
In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with an electric hand mixer, blend sugar, whole egg, egg white and vanilla. Add Junior Mint Butter MIxture. Gradually blend in dry mixture. Be careful- this process gets dusty!
Spread batter into pan. Bake for 26-30 minutes or until it passes "the toothpick" test.
Allow to cool for 5 minutes. The brownies should be warm, but not hot. Equidistant apart, press 9 Junior Mints into the top of the brownies. Allow to cool completely then remove foil lining and cut into 9 squares, each with a Junior Mint in the center.
If you've tried this recipe, come back and let us know how it was!