Line a 20cm x 20cm (8x8") baking tray with baking paper and then lightly dust the paper with cornflour or arrowroot powder.
Into the bowl of a stand mixer, pour in ¼ cup (60ml) of cold water.
Sprinkle the gelatine powder on top of the water and let it stand and look for 5 to 10 minutes.
In a small saucepan combine the honey, the remaining ¼ cup (60ml) of water, and the salt.
Heat over medium heat until the mixture reaches 115˚C (240˚F).
Turn the stand mixer on low speed, then carefully pour the hot honey mixture into the gelatine mixture.
Once all the mixture is added, increase the speed to high and whip for 8 to 10 minutes. The mixture should be thick, glossy and will be triple in volume.
Add the vanilla and marshmallow root, if using, and mix until just combined.
Working quickly, spread the mixture into the prepared pan, smoothing the top with a lightly greased spatula.
Let the mixture sit at room temperature for about 4 hours, or until it is fully set.
Dust the top with additional cornflour or arrowroot powder.
Nutritional information is an estimate and provided as a courtesy. The values may vary according to the ingredients and tools that are used. Please use your preferred nutritional calculator for more detailed information.