4 unwaxed lemons, zest and juice only
1 lemon, zest only
10-15 ripe passion fruits, halved and seeds scooped out
400g/14oz caster sugar
200g/7oz caster sugar
4 tsp cornflour
2 heaped tbsp icing sugar
pinch salt
2 tsp white wine vinegar
100g/3Β½oz unsalted butter, cubed
900ml/1Β½ pint double cream
8 medium free-range egg whites
3 medium free-range eggs, plus 1 medium free-range egg yolk
limoncello liqueur, to serve (optional)