If you are not following the Low Fodmap diet, you can also use the same amount of almond meal instead of the ground macadamia nuts.
If you are not following either the Low Fodmap or the gluten-free diets, you can use regular flour.
These cakes freeze very well. Just wrap them individually in aluminum foil and then put them in a Ziploc bag. When you want to eat them, simply defrost them by keeping them at room temperature.