Whisk all of the ice cream ingredients together. Place them in your ice cream machine, and follow the standard instructions for your unit to make the ice cream. Transfer to an air-tight container and keep it in the freezer to harden for a few hours.
Prepare the grill for direct grilling at 500° to 600°F.
Sprinkle the cut side of the bananas with a generous amount of turbinado sugar. Let sit while the sugar dissolves into the banana a little.
Place the chocolate in a double boiler to melt. Combine the remaining chocolate sauce ingredients in a separate pan and bring to a boil over medium heat. Remove the chocolate from the heat of the double boiler and whisk in the ingredients from the other pan. Let rest at room temperature to thicken while you grill the bananas and cherries.
Place the flat, sugar-coated side of the bananas on the grill grate. Leave them in one place to caramelize while you also grill the cherries. You can move the cherries as much as you like, but the bananas need to be left alone. When done, the sugar will have browned and caramelized on the bananas. You’ll need a very thin and flexible spatula to remove them with the delicious sugary coating intact.
Assemble 6 sundaes, each with 2 scoops of ice cream, 1 banana, 5 cherries, a little chocolate sauce and some macadamia nuts. Whipped cream is optional. Enjoy!
