Prepare the sauce by combining the ingredients in a saucepan and simmer over low heat for 10 minutes. Remove and cool
Peel the mangoes and remove the flesh by cutting away from the seed on the flat side of each fruit. You should have 2 large slices of fruit from each mango.
Brush the mango slices with some of the sauce and let stand for 5 minutes. Oil a clean grill, place the mango slices in a grill basket, and grill over a low fire until lightly browned and glazed, turning often, basting with the sauce. The grilling should take about 4 to 6 minutes.
To serve, sprinkle the coconut over 4 serving plates, place a mango slice and a scoop of ice cream over the coconut, drizzle remaining sauce over all, and top with the macadamia nuts.
