Cut 4 to 10 inch squares of foil and grease the center of each with butter. Peel the bananas, put one on one end of each piece of foil and divide the honey and coconut between them. Fold over the foil and double seal all around the 3 open edges, leaving plenty of air space between the banana and the top layer of foil. The parcels should look like little fat cushions. You cook the foil parcels in a large pan of boiling water in a steamer for 40 minutes.