Lemon Meringue

Directions

1. MAKE THE MERINGUES:
2. NOTE: If your oven is not big enough to bake all three meringues at the same time, make a third of the recipe at a time and bake each third individually.
3. Preheat oven to 425°F (220° C). Place baking paper on 3 large baking trays and by using the bottom of a 22-centimeter (8 1/2- to 9-inch) cake tin, draw 3 circles on each piece of paper.
4. Beat the egg whites with the cream of tartar and salt until stiff peaks form.
5. While the beater is still running, add the sugar 1 tablespoon at a time until all the sugar has been mixed in and the meringue is thick and glossy.
6. Sift the cornstarch over the mixture, add the vinegar, and run the beater until everything is combined.
7. Scoop each third onto a drawn circle and shape the meringue within the drawn lines, keeping the top of the meringue quite even.
8. Place in the oven and immediately reduce the heat to 300° F (150° C) and bake for 30 minutes. Reduce the heat to 250° F (120° C) and bake for another 45 minutes.
9. Switch the oven off and let the meringues cool inside the oven.
10. While the meringues are baking, make the curd and chocolate shards and store until required. To make the curd, start by placing the sugar and zest in a food processor and blitz together until the sugar is fragrant and light yellow.
11. Set a metal bowl over a large saucepan of boiling water, making sure the bowl does not touch the water.
12. Place the lemon-sugar mixture in the bowl with the butter, lemon juice, and salt and stir over the heat until the butter is melted and sugar dissolved. Slowly whisk in the eggs and continue whisking over the heat until the mixture thickens and coats the back of a spoon.
13. Spoon the curd into a bowl, cover, and place in the fridge to chill for at least 2 hours.
14. Melt the chocolate in a metal bowl set over a large saucepan of boiling water, making sure the bowl does not touch the water.
15. Once melted, spread the chocolate evenly onto a piece of greaseproof paper.
16. Cover with another piece of paper and gently press to release any bubbles. Roll the pieces of paper into a thin tube and place in the fridge for 2 hours to set.
17. When you are ready to assemble the cake, unroll the tube -- as you unroll, the chocolate will break and you will have the shards to decorate with.
18. ASSEMBLE THE CAKE:
19. Mix the drained yogurt, half of the lemon curd, pistachios, and lemon zest.
20. Whip the cream until stiff. I prefer not to sweeten the cream, as everything else in the cake is sweet enough.
21. Place one meringue layer on a cake stand. Spoon over half of the lemon curd and spread it evenly over the meringue.
22. Place the second meringue layer carefully on top. Spoon over the other half of the lemon curd, then spoon over the pistachio-yogurt mixture and spread it evenly.
23. Place the third meringue on top. Spoon over the whipped cream and sprinkle with the white chocolate shards.
24. The cake will hold its shape so you can make it before the meal and serve it as dessert, but I would not let it stand for more than 3 hours at room temperature.