Spread the macadamia nuts out on a baking sheet and bake for 4 minutes, then mix/flip, and cook for another 2-3 minutes. Remove from the oven and let cool.
Prepare an 8x8 pan with butter and parchment paper.
In a saucepan over medium-low heat, melt the butter. Add the sugar and cook for another minutes.
Remove the pan from the heat and add the cocoa, then salt. Stir to combine, and let cool 5 minutes.
Mix in the vanilla extract, then the eggs, one at a time.
In a separate bowl, whisk together the baking powder, espresso powder, and flour. Combine with the wet ingredients and mix to just barely combine.
Coarsely chop or crush the macadamia nuts. Mix ¾ of the nuts, and ¾ cup chocolate chips, into the batter.
Spread the batter into the prepared pan, and bake at 350 F for 23-25 minutes. The top should have a flakey layer and edges should be set, but not darkened.
Let the brownies cool completely before proceeding.
Heat the heavy cream in the microwave until almost boiling. Remove, add remaining chocolate chips, and let sit for 90 seconds.
Stir the cream and chocolate chips until completely smooth. Let cool slightly (it will thicken as it cools).
Spread the remaining crushed nuts over the top of the brownies, then pour the ganache over top. Let set at least one hour before slicing, preferably more.
Recipe by The Kitchen Paper at http://c02.ddd.mwp.accessdomain.com/macadamia-mocha-brownies/