If serving the lemon posset without the cake, prepare a double recipe to make five ½cup servings. After combining the cream and the lemon syrup and straining it into the 2cup glass measure, pour equal amounts into five small ramekins or Pyrex custard cups. Refrigerate, uncovered, for 4 hours. Once the mixture is set, cover each ramekin tightly with plastic wrap. Let the possets sit for 10 minutes at room temperature before serving.