Roast the macadmia nuts at 350 degrees for 10 minutes or until light brown and fragrant. Set the nuts aside.
Combine the dry ingredients together in a small bowl and set aside.
In the bowl of your stand mixer, mix the eggs and brown sugar for 10 minutes or until the mixture is well combined and has a silky texture. Add in the coffee extract, vanilla, and lemon zest.
Stir in the dry ingredients and mix until just combined. Then add in the dark chocolate chunks and the nuts. Mix until combined.
On your prepared baking sheet, transfer the dough onto the sheet and combine the dough into 2 logs that are about 6 inches by 2 inches. See my other biscotti recipe for detailed instructions. If the dough is sticking to your hands, run your hands under water and form the dough into the logs with wet hands.
Transfer the sheet into the oven (350 degrees) and bake for 35 - 40 minutes or until the logs are firm to the touch. These biscottis take longer to bake than the other ones. Remove the tray and let cool for 10 minutes. Using a serrated knife cut the logs into 1 inch wide slices. Placing them face side down, put them back in the oven and cook for another 15 minutes, flipping the biscottis half way through. Ensure that the biscottis are fully cooked, it may take longer than 15 minutes.
Let them cool completely before transferring them into an air tight container.