Pre-heat oven to 350°F (180°C). Line an 8-inch (23cm) metal baking pan with parchment paper.
In a large bowl, combine butter, brown sugar, granulated sugar, eggs, flour, cocoa powder and baking soda. Fold in TURTLES®.
Pour batter into prepared baking pan and spread evenly. Bake for 25 minutes.
Top layer:
Wait until brownies have been baking 15 minutes to prepare the top layer. In a large heavy bottom pot, combine butter, marshmallows and cocoa powder (if using).
Cook over medium-low heat and stir until completely melted. Add Rice Krispies® cereal. Stir until evenly coated.
When brownie layer is cooked, remove from oven and gently press the Rice Krispie® layer over the baked brownie base as evenly as possible.
Flatten layer with the back of a spoon. Place the AFTER EIGHT® mints on top, slightly overlapping until top is covered. Return pan to oven and bake for 3 minutes Remove from oven and cool completely. Refrigerate for 1 hour.