Method

1. Very lightly grease a 1-litre jelly mould with oil, then make the rhubarb layer. Put the rhubarb and caster sugar in a pan with 250ml water, cover with a lid and simmer for 5-8 mins until the rhubarb is really soft, then remove from the heat. Put the gelatine in a small bowl of very cold water to soften.

2. Line a large sieve with muslin or a J-cloth, place over a bowl and pour in the rhubarb liquid, then leave to drip through. Once all the liquid has dripped through, return the juice to the pan over a low heat. If your rhubarb juice isn’t very pink, you can add a drop of food colouring. Once soft, remove the gelatine from the water and squeeze out any excess, then add to the warm rhubarb juice, stirring until the gelatine dissolves. Pour half the rhubarb liquid into your jelly mould and put in the fridge to set for 3 hrs. Leave the remaining rhubarb juice at room temperature.

3. Meanwhile, make the custard layer. Put the milk, cream, and vanilla pod and seeds in a pan, heat gently until just simmering, then remove from the heat. Soak the gelatine in a bowl of very cold water. In a large bowl, whisk the sugar, egg yolks and custard powder until smooth and pale. Pour over the warmed milk, whisking to combine. Pour the hot mixture into the pan and heat gently until thickened slightly, then remove from the heat. Remove the gelatine leaves from the water, squeeze out any excess liquid, add to the custard and stir well. Leave to cool.

4. Once the first layer of jelly has set, pour over half the cooled custard layer. Chill for a further 3 hrs.

5. Repeat the process with the remaining jelly, making sure each layer is well set before you add the next. If the jelly starts to set at room temperature, you can reheat it very gently on the hob – just make sure it doesn’t boil, as this will stop the gelatine from setting. Once the jelly has had its total setting time, ease the edges away with your fingers, then turn out onto a plate (you may have to give a little jiggle to dislodge the jelly) and serve.