Sprinkle powdered gelatin over the water and let it sit for 4-5 minutes.
Heat the mixture for 20-30 seconds in the microwave and stir - the gelatin should dissolve entirely
Whip 2 cups of cream in a large bowl on medium speed until soft peaks form - this can take anywhere from 4-8 minutes.
Add the sugar and whip until stiff peaks form. When you lift your beaters from the cream it make peaks that will stand up
Beat in your mango puree and cardamom powder, you may need to scrape the bowl from the bottom with a spatula to fold in your puree (see video) to evenly incorporate it. Do not stir!
Pour your gelatin in through a sieve and beat for 10 seconds.
Transfer the mango mousse into your serving dish or dishes and chill for at least two hours. Keeps well in the fridge for up to 4 days.
I left a range for the mango puree because 1 ½ will give you a lovely pleasant mango taste and 1 ¾ a more robust one. Pick whatever you prefer!