Soak the macademia nuts in water overnight for 8 hours, then drain and rinse.
In a high-speed blender, blend the nuts, filtered water, agar agar, salt and citric acid on the highest speed for 4-5 minutes or until smooth and creamy.
Heart the mixture in a non-stick pan over low/medium heat, stirring continuously, until it reached 185F (85C). The mixture should start to thicken once it reaches the right temperature. Stir vigorously for 1 minute, then remove from heat.
Pour the vegan feta mixture into a small spring form or a rectangular container and place it into the fridge for 1-2 hours to set.
Once the feta is firm, remove it from the container and cut into bite-size cubes.
Mix vinegar or lemon juice, olive oil, sliced garlic, fresh herbs, and salt in a jar to create the marinade, then add the feta cubes. Make sure all cubes are coated in the marinade, then close the jar and place it in the fridge overnight. The feta cubes will soak up the flavors of the marinade and be ready to enjoy the next day.