1. Line a 30 x 20 cm shallow cake tin with foil and brush with melted butter or oil.
2. Using electric beaters, beat the sugar and 1/2 cup water for 3 minutes.
3. Combine the gelatine with 1/2 cup water in a small bowl. Stand the bowl in hot water until the gelatine becomes spongy, then stir until dissolved. Add to the sugar mixture and beat with electric beaters for 10 minutes, or until thick and white. Add the vanilla essence. Pour into the tin and spread out evenly. Leave overnight to set at room temperature.
4. Preheat the oven to 180C. Spread the coconut evenly on a flat baking tray. Bake for about 3 minutes, or until golden (watch the coconut carefully when toasting as it can quickly burn). Pour onto a plate to cool.5. Turn the marshmallow out of the tin and cut it into cubes. Place the toasted coconut in a plastic bag and add a few cubes of marshmallow at a time. Shake to coat.
Store in a single layer in an airtight container in a cool dark place for up to a week. Keep flat.