In a small bowl, sprinkle gelatin over water and let it sit for 5 minutes to bloom.

In a mixing bowl, combine mango puree, sugar, and vanilla extract. Mix well.

In a separate bowl, whip the heavy cream until soft peaks form.

If using gelatin, gently heat the bloomed gelatin until dissolved, then mix it into the mango mixture.

Fold the whipped cream into the mango mixture until fully combined.

Spoon the mousse into serving glasses and refrigerate for at least 2 hours before serving.