Put 600 grams of mango into a large measuring bowl. Use fresh mango if you have it, but frozen chunks will do just fine.
Peel the orange and squeeze its juice into the same bowl. You could just put in the whole orange if you prefer, but the final product won't be as smooth.
Heat it in the microwave for at least five minutes.
While the fruit is in the microwave, put the kettle on.
While the kettle heats up, put three tablespoons of gelatin into a cup or bowl.
Add about a cup of water to the gelatin and stir till it until it starts to dissolve. The fruit should be just about done, so let the gelatin sit for a short while.
Once the orange juice and mango have been heated in the microwave, put it in a blender. Take care not to spill the orange juice while pouring it as it's vital for the consistency.
blend on the highest setting until the consistency is smooth and there aren't any chunks.
Make sure there aren't any chunks in the mixture. You may also want to check the gelatin and make sure it's dissolved into the boiling water.
When the fruit is blended to a smooth consistency, pour the gelatin into the blender. It is often advisable to start at a lower setting and work your way up to the highest so it doesn't spill over.
Blend the whole mixture well, but you may wish to stir the surface a bit with a spoon to prevent all the gelatine from collecting there.
When you're done, check that the mixture is blended.
Pour the mixture back into the measuring cup (or into a bowl of you prefer) and let it cool.
Leave it uncovered on the counter for 15-30 minutes so it isn't too hot when you cool it in the fridge.
Put the mixture in the refrigerator to cool it further.
If you want to eat it on the same day, take it out after a little while and put it in the freezer for an hour or so. Otherwise you can just leave it in the fridge overnight.
It can be eaten on its own or with whipped cream, berries, or even yogurt.