Slice the pineapple in half with leaves intact. Cut the core from each pineapple half and discard. With a small sharp knife carefully cut the remaining pineapple out of the shell. Cut into 1-inch cubes and combine with additional 2 cups of pineapple chunks.
Combine coconut, gingersnap cookies and macadamia nuts. Set aside.
Whisk together sweetened condensed milk and dark rum. Set aside.
In the cored pineapple halves, layer half pineapple chunks, sprinkle half of coconut/gingersnap mixture, drizzle of half sweet condensed milk/rum mixture; repeat.
Bake at 325 degrees for 20-25 minutes or until golden brown and bubbly; about 20-25 minutes. Keep an eye on it so it doesn't brown too quickly. Tent with foil if necessary.