1Sprinkle the gelatin over the cold water; let stand for 5 minutes.
2In a 3-qt. saucepan, warm the cream with the sugar, salt, and vanilla over medium-high heat. DO NOT LET IT BOIL!
3Stir in the gelatin until throughly dissolved.
4Take the cream off the heat and cool about 5 minutes.
5Put the sour cream in a medium bowl.
6Gently whisk in the warm cream a little at a time until smooth.
7Taste for sweetness; it may need another teaspoon of sugar.
8Rinse 2/3 cup ramekins, custard cups, or coffee cups with cold water (do not wipe out).
9Fill each one 3/4 full with the cream.
11To serve, either unmold by packing cups in hot towels and then turning each out on a dessert plate, or serve in their containers.
12Serve alone or with fruit, drizzled liqueor, or purred raspberries.