In a medium sized saucepan, heat ½ cup heavy cream, milk, sugar and coffee beans until it is near-boiling. Stir to dissolve the sugar. Remove from the stove, cover, and allow to steep for one hour.
Pour the remaining heavy cream into a bowl and set it on ice over a larger bowl to create a water bath. Set aside.
In a mixing stand with the balloon attachment, whisk the eggs yolks for 1 minute until its pale yellow in color. While the eggs are whisking, reheat the dairy/coffee mixture until it begins to steam but not boil. Turn the mixer on medium and gradually drizzle in ½ of the hot dairy/coffee mixture into the beaten eggs.
Once the mixture has been tempered and combined, pour it back into the saucepan with the remaining dairy/coffee mixture. Heat over medium-low, stirring constantly for a few more minutes or until the consistency is thick enough to coat the back of a spoon when dipped inches Pour the mixture through a sieve into the bowl of chilled cream.
Discard the beans and remnants from the sieve. Whisk in the espresso and vanilla extract until combined. Cover the bowl with plastic wrap and chill the custard for 6-8 hours.
Pour the custard base into the ice cream canister and churn according to the manufacturers instructions until the mixture resembles soft served ice cream. About 2 minutes before the churning is complete, sprinkle in the macadamia nuts and chocolate chunks.
Transfer the ice cream to an airtight container and press plastic wrap against the surface. Cover the container and freeze the ice cream for 4-5 hours or until firm.