6 large egg yolks (reserve the whites for the meringue)
1 whole egg
Candied lemon slices:
250g caster sugar
250g unsalted butter, softened, plus extra for the tin
300g caster sugar
400g self-raising flour
1 tsp baking powder
1/2 tsp salt
4 unwaxed lemons, zested
1 lemon, juice only
150g full fat greek yoghurt
For the meringue:
230g caster sugar
4 fresh egg whites, at room temperature
1 tsp cream of tartar
Make the lemon curd: In a heat proof bowl, mix together the cornflour and sugar, then add the butter and juice of 5 lemons. Place the bowl over a pan of just-simmering water, taking care not to let the bowl touch the water.
Stir with a whisk until the sugar and butter have melted. Add the egg yolks and egg and whisk well to break them up and mix through.
Keep stirring over a gentle heat until thick and creamy. Sieve the curd into a clean bowl and cover with clingfilm. Leave to cool then put into the fridge while you make the rest of the cake.
Make the candied lemon slices: Wash two lemons and slice into 3 millimeter thick rounds, discarding both ends and any pips.
Put the sugar and water into a saucepan and bring to a simmer, then add lemon slices and simmer for 15 mins.
Remove lemon slices and set aside on grease proof paper.
Make the lemon sponges: Butter the tins and line the base with baking paper. Preheat the oven to 180C / 160C fan.
Put the butter and caster sugar into a large mixing bowl and use an electric hand whisk to beat the mixture until light and fluffy.
Add the eggs one at a time, beating well after each one.
Mix together the flour, baking powder and salt. Add to the cake mixture and use the hand whisk on low speed to combine, then mix through the lemon zest, lemon juice and greek yoghurt.
Divide the mixture between two lined sandwich tins. Bake for 25-30 minutes, until firm to the touch and a skewer comes out clean. Leave to cool in the tin for 15 minutes then transfer to a wire rack to cool fully. Leave the paper on the bottom of each sponge until you are ready to assemble the cake.
Make the meringue: Put the caster sugar and water into a small saucepan and stir until the sugar has melted, then bring to the boil. Leave the saucepan without stirring, until it reaches a fast boil. Use a sugar thermometer to check the temperature of the sugar syrup - it needs to reach 120C.
Meanwhile, put the egg whites into the bowl of a stand mixer and whisk until frothy, then add the cream of tartar and whisk on high speed until it reaches soft peaks.
Once the sugar has reached 120C, with the stand mixer running on low speed, carefully pour the sugar syrup down the inside of the bowl into the whipped egg whites. Keep whisking until the meringue has formed firm peaks and has cooled right down, then switch off the mixer. Transfer a third of the mixture to a piping bag fitted with a large fluted nozzle..
Assembling the cake: Trim the top of one sponge level then cut each cake into two layers.
[could do the ruler and toothpick thing to show how to cut even layers?]
Starting with the trimmed cake, place the bottom layer onto a serving plate then spoon over a thick layer of the lemon curd. Add the levelled layer of cake on top of that and repeat the layers of lemon curd and cake, finishing with the domed cake top.
Spread the remaining meringue mixture over the top and side of the cake, creating a dome on top. Working quickly while the meringue is still pliable, use the rounded end of a small palette knife to make stripes up the outside of the cake, all the way around. Pipe a mound of swirls and stars on top of the cake. Use a blowtorch to lightly toast the sides of the cake and the decoration on top. Wedge lemon slices upright in between the swirls. Then serve!