Zest 1 large lemon using a grater, grate only the bright outer yellow layer, and avoid the bitter white layer underneath.
Over high heat, combine together the heavy cream, sugar and lemon zest, whisk constantly and bring to a boil, reduce heat to medium to keep the mixture at a steady boil for 8 minutes, watch closely, if the mixture foams, briefly remove from heat, stirring constantly. keep boiling until the mixture reduces down to 2 cups, that brings a a perfect consistency, (measure it up while boiling).
Remove the pot from heat and strain: Strain the liquid through a fine-mesh strainer to get rid of the lemon zest.
Add the lemon Juice: Add the lemon juice and whisk well to infuse everything together. Let it cool down for 5minutes.
Pour the lemon posset in ramekins, leave it to cool down completely and refrigerate for at least 4 hours before serving.
To make the passion fruit posset, swap the lemon juice to passion fruit juice,
To make the passion fruit juice, cut the passion fruit in half, scoop out the flesh, and transfer to a handmill or a potato ricer, (the holes in the handmill are smaller than the seeds in the passion fruit pulp) secure the mill or potato ricer above a bowl, turn the crank and the blade will puree the passion fruit pulps through the wholes in the disc, make sure to scrape any remaining soup off the bottom, and now you've got the passion fruit juice, replace passion fruit juice for lemon juice, and omit the lemon zest. Add some passion fruit seeds, if you desire, to your passion fruit posset, they are edible, nutrisious and add a lovely contrast. Watch the video tutorial below.