Line a deep loaf tin with a double layer of plastic wrap, you could also use baking parchment.
Wash and slice the rhubarb. Place in a pan with the 100g of caster sugar, 2 tablespoons of water and the ginger cordial. Poach on a low heat until the rhubarb is tender but still holding its shape, how long depends on how thick it is, but around 5 to 10 minutes. Transfer to a bowl and leave to cool.
Separate the eggs, put the whites in one bowl and the yolks in another. To the yolks add the 100g of icing sugar. To the whites add a pinch of salt. Measure the cream into a third separate bowl. In a fourth bowl break the meringues into pieces and mix with the crystalized ginger.
With an electric hand whisk, first whisk the egg whites until peaks form. Then whisk the cream until thick. Then whisk the egg yolks and sugar until pale and thick.
Fold the yolk mixture into the bowl of whipped cream until well combined.
Add the whisked egg white and most of the meringue and ginger mixture to the egg and cream mixture, keeping some back for the top. Fold in with a metal spoon to keep the air in, until completely mixed.
Spoon a third of the mixture into the prepared tin, bang on the work surface to settle and release any air bubbles, then place in the freezer for 45 minutes. Place the rhubarb and the cream mixture in the fridge.
Remove from the freezer and place a third of the rhubarb and juice on top. Spoon over another third of the cream mixture and return to the freezer for another 30 minutes.
Once that layer has also set, add most of the rest of the rhubarb and juice but keep the neatest pieces and some juice for decorating. Cover with the last of the cream mixture. Freeze for at least two hours, or overnight.
Don't take the tin out of the freezer until you are ready to eat it, it will come out of the tin and slice easily. Turn onto a plate, remove the plastic wrap and decorate with the remaining broken meringue, ginger pieces and rhubarb. Drizzle with the rest of the rhubarb juices, slice and serve.