Preheat your oven to 350 degrees F. Lightly oil an 8" x 8" baking pan, then line it with parchment paper.
Add all of the ingredients for the brownies to a high-powered blender. Blend until completely smooth. Pour the batter into the prepared baking dish and smooth into an even layer.
Bake for 35 to 45 minutes, or until the center of the brownies sets up. Remove from the oven and cool for 1 hour.
Meanwhile, prepare the mint topping by mashing all topping ingredients together in a bowl.
Once cooled, spread the mint topping over the brownies and sprinkle with cacao nibs, if desired. Cut and serve.