Start by roasting the rhubarb. Heat oven to 180ºC/350ºF/Gas Mark 4.
Cut the rhubarb into 5cm (2 inch) lengths. Pop in a baking dish with the sugar, lemon juice and one of the vanilla pods. Roast for about 15 - 20 minutes until soft and juicy but not falling apart. Allow to cool thoroughly.
Next, make the panna cotta. Pour the cold milk into a small bowl, sprinkle in the gelatine and mix thoroughly. Then pour the mix into a saucepan with the cream, honey, salt and the second vanilla pod and set over a medium heat until just barely simmering stirring well until the honey dissolves. Then turn off the heat. Remove the vanilla bean and scrape the seeds into the pot.
Pour the mixture into 4 to 6 ramekins or glasses and once cool, cover and chill in the fridge until set or overnight.
When you are ready to serve top each panna cotta with a spoonful of rhubarb and its juices and a sprinkle of chopped pistachios and bee pollen.