Combine Sugar, Salt, Cream, and Lemon Zest in a Medium Saucepan. Turn heat to medium, stirring occasionally, until it comes to a gentle simmer.
Simmer Cream for 5 minutes, stirring frequently to prevent burning. Combine the Raspberries and Lemon Juice in a bowl.
Add Raspberries and Lemon Juice into cream mixture. Return to simmer. Stir frequently and simmer for 5 more minutes.
Remove from heat and pour through a mesh strainer.
Push seeds around, taking care to get all of the liquid.
Pour posset mixture into ramekins and place in the fridge for at least 2 hours to make sure they are completely set.
Before serving, beat the Heavy Cream and Powdered Sugar into whipped cream. Dollop each Posset with whipped cream and garnish with raspberries and a mint leaf. Enjoy.