Place the rhubarb, 50g of the caster sugar and 1 tbsp water into a saucepan over a medium heat for around 10 mins, until tender.
Leave to cool and then puree in a blender, chill.
Whisk the egg yolks, 400g caster sugar and salt until pale and thick.
In a saucepan gently heat cream, milk and vanilla extract over a medium heat until just reached boiling point.
Pour over the egg and sugar mixture, whisking constantly.
Return the mix to the saucepan and heat gently until thickened.
Remove from the heat and leave to chill.
Fold in chilled rhubarb puree and then transfer to ice-cream machine if using.
Otherwise transfer to a shallow freezer-proof container.
Place in to the freezer for 2 hours until frozen around the edges.
Beat well with a fork to break up ice crystals.
Freeze again for 2 hours. Beat and freeze until firm.
Serve in bowls with your chice of topping.