For the rhubarb consommé:
Place the rhubarb and sugar in a heavy-bottomed pan and slowly heat until all the juice is released. Pass through a sieve and allow to cool slightly, saving small pieces of rhubarb for a garnish. Add the gelatine and pour into six small individual moulds to set.
For the meringues and garnish:
Heat the oven to 100C/Gas Mark ¼. Line a large baking sheet with baking parchment. Using an electric mixer or electric hand whisk, beat the egg whites with the wine vinegar until they begin to froth and increase in volume.
Now whisk in two-thirds of the sugar, a little at a time. When stiff peaks form, add the remaining sugar and sift in the cornflour. Fold in, using a large metal spoon, until just incorporated. Spoon the meringue into a piping bag and start to pipe small kisses on the baking sheet. Place these into the oven and let the meringue kisses dry out for 35-45 minutes. Turn off the oven but leave them in there with the door open to cool completely.
When the jelly is set, top with mini meringues and garnish with pieces of cooked rhubarb, thin slices of orange and a few sprigs of mint.