01 - Pour heavy cream into medium saucepan. Add granulated sugar. Place over medium heat, stirring gently until sugar completely dissolves and mixture just begins to simmer. Do not allow to boil.
02 - Remove saucepan from heat immediately. Stir in fresh lemon juice and grated zest. Mixture will naturally thicken as acid reacts with cream proteins.
03 - Let mixture cool at room temperature for 10 minutes. Pour evenly into 4 individual ramekins or dessert glasses.
04 - Refrigerate for minimum 3 hours until posset achieves firm, pudding-like consistency. Texture should be silky and hold shape when spooned.
05 - Serve chilled. Garnish with fresh berries, additional lemon zest, or shortbread cookie if desired.