This is one of Jason's parents' staples. Macadamia nuts are big here, they even call them mac nuts. This recipe came from Alton Brown.
1 1/4 cups coarsely ground (or well chopped) roasted mac nuts
1/2 cup bread crumbs (it calls for panko but I just used regular ones)
2 tablespoons flour
1/4 cup butter, melted
4 mahi mahi fillets, 6-8 ozs each
salt and pepper
2 tablespoons coconut milk
Preheat oven to 425. In a medium bowl, stir together the nuts, panko, flour and butter. Set aside.
Line a baking sheet with aluminum foil and brush liberally with oil. Place the fish on the foil and sprinkle each piece with salt and pepper on both sides. Bake for 5 minutes. Remove from the oven and brush each fillet with coconut milk (Jason's mom doesn't use the coconut milk, I'm not sure why but the topping sticks fine without it). Divide the nut mixture among the tops of each piece, patting the mixture to spread and adhere to the fish. Return to the oven and bake for 5-10 more minutes, or until the crust is golden brown.
Remove from the oven and let stand 10 minutes before serving.