Pour the double cream into a saucepan, add the caster sugar and lemon zest, and heat gently over medium heat. Stir until the sugar has dissolved, then bring to a simmer. Let it bubble gently for 2–3 minutes, stirring now and then.Tip:I always use a fine zester like this to get loads of bright lemon flavour without the bitter pith.
Take the pan off the heat and stir in the lemon juice. Mix well – you’ll see the cream start to thicken slightly.
Pour the mixture into 4 small glasses or ramekins like these. Leave to cool at room temperature, then chill in the fridge for at least 3 hours (or overnight) until set.Tip: Strain through a fine mesh sieve like this if you want a super smooth texture.
Just before serving, scatter fresh summer berries over each posset. Add a couple of shortbread biscuits on the side and enjoy!