Put the creams, mascarpone, sugar, and salt in a metal bowl and mix together well. Let sit 30 minutes.
In a small saucepan, place the gelatin in the water and let it sit 10 minutes. Stir for a minute over low heat to completely dissolve.
Meanwhile, put the bowl of creams over (but not in) simmering water, and warm the creams for 3 minutes, stirring constantly. Add and mix in the