Panna cotta simply means cooked cream. It is an Italian dessert a soft set custard.
Trim the top and bottom of the rhubarb. Cut into 1inch lengths and place in a roasting tin. Using a fine grater, zest the orange into the tin and then squeeze oven the juice of half the orange. Add the sugar and toss together. Cover the tin with foil and cook in a 170°C / 150°C fan oven. Allow to cool then refrigerate until required.
To prepare the panna cotta, put gelatine into a small bowl of cold water, make sure it is completely submerged.
Put the cream, milk and sugar into a saucepan. Split the vanilla pod in half lengthways and scrape the seeds out with your knife. Add both the seeds and the pod to the cream. Heat the cream until hot just beginning to bubble around the edges and give off a little steam do not allow to boil. Switch off the heat. Remove the gelatine from the water, it will be soft and jelly like now, squeeze to remove excess water then stir into the hot cream. Continue to stir for a moment until the gelatine dissolves.
Remove the vanilla pod, (allow to dry and store in a jar of sugar and you will have vanilla scented sugar). Divide the mixture between 4 ramekins or 4 glasses. Refrigerate for at least 4 hours until set.
To un-mould dip the ramekins in a bowl of boiling water for 4 - 5 seconds. Turn out onto a plate and spoon over some of the rhubarb and the pink syrupy juices. If serving in a glass no need to turn out simply spoon a little of the rhubarb over and serve.