Preheat the oven to 170C/340F. Line and grease 2 baking trays.
Whisk the egg whites in the clean bowl of a kitchen stand mixer fitted with a whisk attachment on medium/high until soft peaks form (this can be done using a hand whisk).
Add the maple syrup, vanilla, salt and cocoa and whisk on medium until combined. Fold in the nuts.
Use an ice-cream scoop, or a 1/4 or 1/3 cup measurement, to make 10-11 cookie mounds on the baking tray. Use 2 baking trays to ensure that the cookies do not spread on top of each other.
Flatten each mound slightly into a round shape.
Bake for approximately 10 minutes (depending on your oven this may be up to 13-15 minutes), or until cooked on top and firm on the bottom. The cookies will firm up open cooling.
These Chocolate Brownie Macadamia Cookies are best eaten within 24 hours of baking.