Add the gelatine to a bowl and cover with cold water. Leave to soak for at least 5 minutes until softened.
Meanwhile, add the cherries with syrup and 25g caster sugar to a small saucepan and bring to a gentle simmer for 3-4 minutes, stirring until the sugar has dissolved. Use a hand blender to turn the cherries into a purée and put through a sieve into a large jug. Add 1 tbsp lemon juice, then stir in enough hot water to make 425ml. Drain the gelatine leaves and stir into the cherry juice until dissolved. Pour into your trifle bowl and leave to set for 4 hours.
Place 400ml cream in a medium pan over a gentle heat and heat it to just simmering, stirring occasionally with a wooden spoon to avoid it sticking to the pan. Meanwhile, whisk together the egg yolks, 25g sugar and cornflour with 1 tsp vanilla extract in a medium bowl. Continue whisking the egg mixture as you gradually add the warmed cream. Once everything is combined, return all of it back to the saucepan. Continue to heat gently, whisking continuously for 5 minutes or until the custard is thick and smooth. Pour the custard into a jug or bowl, cover the surface with clingfilm and leave to cool, transferring to a fridge to chill completely.
Cut the madeira cake into 2cm cubes and spread out on a tray. Sprinkle with the limoncello and leave to soak. Add the ricotta to a medium bowl along with 25g caster sugar and 1 tsp vanilla extract. Beat until smooth. In a separate bowl, whisk the remaining double cream by hand until very softly whipped – it should barely hold peaks. Fold into the ricotta until just combined. Fold in the lemon curd so it’s rippled through.
Once the jelly is set and the custard is fully chilled, pour the custard over the jelly and spread so it’s even. Spread the madeira cubes across the custard in an even layer. Roughly chop the pitted cherries and add on top of the sponge. Add the lemon ricotta cream, spreading out evenly. Transfer the whole dish to the fridge to chill.
In a small saucepan, combine the remaining caster sugar with 125ml water. Heat over a high heat, brushing down the sides of the pan with a pastry brush dipped in water. Using a sugar thermometer, cook until the sugar syrup registers 120°C.
Meanwhile, wipe the inside of a stand mixer bowl with a lemon wedge. Add the egg whites and mix on a medium speed for 2 minutes until soft peaks form. With the mixer still going, slowly add the hot sugar syrup. Once it’s all added, increase the speed to high and whisk for 5 minutes until thick and stiff.
Remove the trifle bowl from the fridge and pile on the Italian meringue mixture. Shape to create peaks and give height. Using a kitchen blow torch, carefully brown the meringue. Place the remaining whole cherries in the centre, then serve.