For the rhubarb jelly, combine the rhubarb, sugar, ginger and 200ml of water in a saucepan. Bring to a simmer and cook for 15 minutes or until the rhubarb is soft

Pass the mixture through a sieve. Soak the gelatine leaves in a bowl of cold water for 5 minutes. Return the rhubarb liquid to the saucepan, heat through then remove from the hob. Squeeze the excess water from the gelatine and add to the rhubarb liquid. Stir to dissolve

Pour the jelly mixture into 4 serving dishes (preferably old-fashioned glass trifle glasses) and set aside in the fridge until set

To make the crumble, preheat the oven to 150°C/gas mark 2. Combine the caster sugar, Demerara sugar, flour, butter and oats in a food processor and blend until the mixture resembles breadcrumbs

Line a baking tray with baking paper and scatter the crumble over it. Bake for 40 minutes, then remove from the oven and leave to cool. Crumble the mixture with your fingers and set aside until ready to serve

To prepare the roast rhubarb, preheat the oven to 220°C/gas mark 7. Cut the rhubarb into 2cm pieces and lay them on a lipped baking tray. Peel and grate the ginger and sprinkle it over the rhubarb along with the sugar. Splash with a little water and bake until the rhubarb is tender, but still has some bite – about 10-12 minutes

Remove the rhubarb from the oven and leave to cool on the tray

To make the custard, roughly chop the ginger and place in a saucepan with the cream. Bring to the boil and then reduce to a low simmer. Meanwhile, whisk the sugar, egg yolks and cornflour together in a heatproof bowl

Pour the hot cream, a little at a time, into the egg mixture, whisking constantly. Return the custard to the saucepan and cook, over a low heat until it thickens, stirring constantly

Strain the custard through a fine metal sieve into a clean saucepan. Put a layer of cling film over the surface to prevent a skin forming and leave to cool

For the ginger cream, whisk the cream in a bowl until soft peaks form. Finely chop the preserved stem ginger and fold into the cream along with the ginger syrup and a little of the crumble mixture

To finish the trifles, top the jelly with a layer of roast rhubarb pieces then pipe on a layer of cooled custard. Cover with the ginger cream and sprinkle with the remaining crumble mixture. Serve immediately