Place whole macadamia nuts into a food processor and process until the nuts resemble a chunky, slightly runny nut butter. Add pitted dates and process until the nuts and dates resemble a slightly runny, pureed paste.
Add the cocoa powder, almond flour, espresso powder and maple syrup to the food processor, pulse slowly to incorporate. Continue to process until the batter comes together almost like pie dough. It should stick together very easily.
Scoop even scoops around the prepared pan. Press the batter into the pan, working from the edges to the center. Chill in the fridge for at least 60 minutes to set the brownie base.
Make the ganache: Place chopped chocolate or chips and heavy whipping cream (or coconut cream) into a heat safe bowl. Place the bowl on top of a small or medium pot filled with about an inch of water. The bowl should not touch the water.
Heat the bowl of chocolate and cream until the chocolate has mostly melted. Remove the bowl from the heat. Stir in the vanilla extract. Let the mixture sit for 5 -10 minutes. Chill in the fridge for 5-10 minutes or until cool to the touch, but still liquid.
Pour on top of the chilled brownie. Chill in the fridge for at least 30 minutes to set the ganache.Top with flaky salt if desired. Slice and enjoy straight from the fridge.