Preheat the oven to 350ºF. Line an 8″ square pan with aluminum foil, leaving some overhang. Lightly spray the foil and set aside. In a large, microwave-safe bowl, add the butter and chocolate, heating in 30 second increments until the chocolate has melted and the mixture is smooth. Cool to lukewarm. Add the eggs, sugar, vanilla, coffee, espresso granules, and salt, whisking to combine. Add the flour and stir, just until smooth. Do not over mix. When the batter has cooled, add the Andes Mints. Fold the mints into the batter using a spatula or spoon, making sure not to overwork the batter (or the mints will melt). Turn the batter out into a prepared pan, smoothing the top lightly with a spatula as necessary. Bake for about 20 minutes, or until the center is no longer glossy. Allow the brownies to cool in the pan on top of a wire rack while you make the topping.