In a 4-quart saucepan, heat the cream, sugar and salt over medium heat until the sugar dissolves, stirring constantly, about 4-5 minutes. If it starts boiling, turn the heat down and simmer gently (I find the sugar usually dissolves before it starts to simmer). Remove from the heat and set aside.
Dissolve the gelatin completely in the boiling water and whisk it into the warm cream mixture.
Cool completely (you can speed this up by using an ice water bath or putting the mixture in the refrigerator, stirring every 15-30 minutes). Whisk the sour cream and vanilla into the cooled cream mixture until smooth.
Spoon into individual serving cups (about a cup per serving - you can use ramekins or small bowls or glass cups or just leave it to chill in one large bowl), cover loosely with plastic wrap and refrigerate for at least 4 hours and up to 24 hours.
Top with fresh berries and/or pomegranate arils and serve chilled.
Gelatin: if you are using the individual packets of gelatin, you'll need a full packet plus a little bit of a second packet. You can get by using just one packet but the finished dessert won't be quite as set up as it is if you use the full tablespoon (learned from experience).Sour Cream: also, since you are splurging on a creamy dessert anyway, I'll tell you, this is much thicker and richer (and more delicious) with regular sour cream - not light and definitely not fat-free.