For the brownies, preheat the oven to 350 degrees F and lightly grease a 9X13-inch baking pan with cooking spray. (If using a glass baking pan instead of aluminum, decrease the baking temperature to 325 degrees F.)
In a microwave safe bowl or in a saucepan on the stove, melt the butter. Stir in the cocoa, sugar and honey. Let cool to room temperature. Whisk in the eggs, one at a time. Stir in the flour, baking powder and salt and mix until combined.
Spread the batter in the prepared pan and bake for 20-25 minutes. Cool completely in the pan.
For the mint layer, whisk together the powdered sugar, butter, milk, mint extract and food coloring (if using) until smooth and creamy. Spread evenly over the top of the cooled brownies. Refrigerate for 15-20 minutes.
For the ganache, heat the cream and butter until just barely simmering. Pour over the chocolate chips and stir until smooth and glossy. Stir in the mint extract. Spread the ganache evenly over the mint layer. Refrigerate for an hour or so until the chocolate layer has set.
Cut into squares and serve. These taste best chilled in my humble opinion.
Notes
Mint Layer: if you like a lot of mint (and/or frosting), consider doubling the mint layer.