1) Slice the lemons in half. Scoop out the lemon flesh. Pat the lemon halves dry with kitchen paper.

2) Using your hands, squeeze out the lemon flesh in a cup until you get about 1/4 cup (60 ml) of freshly squeezed lemon juice.

3) Combine cream and sugar in a small saucepan. Heat gently until it reaches a soft simmer, don't let it overcook. Let it bubble for 2 minutes, stirring so the sugar dissolves fully. This brief simmer is what gives the posset its silky texture.

4) Take the pan off the heat. Pour in the lemon juice (and zest if using) while whisking. The mixture will thicken almost immediately as the acid reacts with the hot cream.

5) If you want it brighter, add a teaspoon more juice. If it tastes too sharp, add a teaspoon of cream.

6) Strain through a fine sieve into the hollowed out lemon boats to remove any zest or tiny curdled bits.