Macadamia nuts are products of the Macadamianintegrifolia or Macadamia tetraphylla tree or from a hybrid between the two. The nuts are high in oil and moisture content when they fall from the tree, but a drying step after collection removes most of the moisture and strengthens the flavor. The flavor may then be enhanced further by oven roasting the nuts.
Nuts that fall naturally from the tree are riper than ones that are shaken out and will have the best flavor, so these are the best for roasting. The fallen nuts then require dehusking and drying in their shells for about two weeks. A final oven dry at the lowest possible temperature setting for 12 hours removes any excess moisture. The nuts require storage in airtight containers, or they will reabsorb the lost water from the air and may turn rancid.
Before roasting the nuts, you will have to remove the shells with a nutcracker. The nuts will have shrunk during the drying process to as little as ten percent of the volume of the shell. Entire nuts or nut halves are best for roasting. At this stage, the raw nuts are also edible.
The high oil content of the nut presents difficulties in roasting as the nuts will burn if not under regular supervision. It is easier to separate the nuts into similar sizes before attempting to roast macadamia nuts that have an even, unburned flavor. If you want salted nuts, you should spray the nuts with a solution of water that has a salt concentration to your taste. Then, you can arrange the nuts on a shallow roasting tray in one or two layers.
An oven preheated to 225 degrees Fahrenheit (about 107 degrees Celsius) is hot enough to roast macadamia nuts. When the nuts develop a golden to tan color, they are ready. This takes at least ten minutes and involves regular turning to avoid burned spots. As the nuts continue cooking even out of the oven, you should also remove the nuts from the tray and place them in a cool place.
Roast macadamia nuts then need to be stored in an airtight container to keep fresh, or they can be mixed up hot from the oven with a bit of butter and eaten immediately. Dishes such as fruitcakes, meat stuffings, and confectionery may also benefit from the addition of the roasted nuts. If you want to store the roast macadamia nuts for a long time, you can also freeze them.