Preheat the oven to 350° F. Grab a 9 or 10″ cake pan that’s at least two inches deep and line the bottom with a round of parchment paper.**
In a large bowl, whisk to combine the flour, sugar, salt, baking soda, and baking powder. Set this aside.
In another bowl, whisk to combine the macadamia oil, milk, eggs, orange zest, orange juice, and Grand Marnier.
Add the dry ingredients to the wet, and whisk until combined, just after the flour disappears. It’s okay if there are a few small lumps here and there.
Pour the cake batter into the prepared cake pan and bake for 60 minutes, until a toothpick inserted into the center comes out clean. Let the cake cool, and serve!
*Macadamia oil can be substituted with the same amount of olive oil, if desired (it will have a different flavor, of course). Macadamia oil is expensive, so you can also do 2/3 cup macadamia oil and 2/3 cup grapeseed oil, to stretch out the macadamia oil. Do not use less than that, or the cake won’t have any flavor.**You can also bake the cake batter in small ramekins instead of one large cake, if desired. Just make sure to start checking the ramekins after 30 minutes.