For the lemon curd:
1) Beat the eggs and sugar in a small stainless steel or copper saucepan (do not use aluminium as it will leave deposits in your curd). Add the lemon juice, zest and butter. Bring to a high simmer and cook until the mixture thickens. Strain immediately through a sieve or cheesecloth.
2) Spoon 30ml of the curd into each of the 10 martini glasses. This is best done while the curd is warm but can also be done once it has cooled if necessary. Chill the glasses with the curd until the curd is cold and set.
1) Split the vanilla pod with a paring knife and scrape the seeds into the sugar. Use your fingers to work the beans into the sugar, making an even mixture. Pour the egg yolks and egg white into the mixture and combine. Don't whip the mixture, but be sure to completely mix it so the color is consistent throughout.
2) Place the cream in a saucepan and bring to a boil. Remove it from the heat and slowly pour it into the egg mixture, stirring constantly. Add the vanilla essence.
1) Meanwhile, preheat the oven to 190C/Gas 5.
2) Pour 85ml of the warm custard mixture into each of the glasses, over the lemon curd. Find a deep baking tray, preferably at least 15cm deep (restaurant supply stores commonly sell these as 'hotel' or 'insert' pans) and place the filled martini glasses in it. Set the tray on the bottom shelf of the oven.
3) Using a water pitcher, pour enough water into the pan to at least cover the stems of the glasses. Ideally, pour in enough to come about a third of the way up the part of the glass that holds the custard. Baking times will vary depending on the amount of water in the baking tray and the type of tray used, but will be somewhere around 45 minutes to 1 hour. The custard is done when you tap the side of the glass and it looks thick and moves as one (as opposed to the centre of the custard jiggling more than the outside).
4) Carefully remove the tray from the oven and let cool at room temperature for about 1 hour. Transfer the creme brulees into the refrigerator to cool and set completely.
5) Sprinkle about a tablespoon of sugar over each of the custards. Use your finger to spread it evenly over the top. Light a blowtorch and turn it to a high setting. Melt and caramelise the sugar quickly.
Cook's note: A flame that is too low, or a prolonged heat directed at the surface of the martini glass, may break the glass. Use caution and practice on one creme brulee moved away from the others so that, if the glass does break, you don't get glass in the other custards.
Creme brulees can be caramelised (burnt) up to 4 hours before service and held in the refrigerator.