Separate the head from the body, peel off the shell and discard the shell and head. Remove the digestive tract by making a slight incision along the spine of the prawn.
Place the prawns in a bowl with some salt and pepper. Add the zest of the lemon and the olive oil.
To cook the prawns:
Heat a frying pan until very hot and add the prawns. Cook for no longer than 2 minutes and finish with a squeeze of lemon.
Preheat the oven to 180'C.
Cut the rhubarb into 3cm batons and place in a roasting tray. Sprinkle over the sugar and roast in the oven for 6-8 minutes or until soft but still holding their shape. Allow to cool in the tray and keep the juices.
Peel and finely dice the shallot and garlic. Pick and shred the mint leaves.
Cut the vanilla pod in half and scrape out the seeds. Put the seeds into a bowl along with the cider vinegar and mustard. Whisk together. Add the chopped shallot and garlic and then whisk in the olive and sunflower oil slowly. Finish with the shredded mint.
Wash the rocket leaves in cold water and use a salad spinner to dry.
Add a spoonful of the dressing to the leaves, mix well and place a neat pile in the centre of the plate. Carefully place alternate pieces of rhubarb and prawn on top of the leaves and finish with a drizzle of the rhubarb juices and the vinaigrette.
«When cooking the rhubarb make sure you do not overcook. Remove it from the oven when it is just beginning to soften and allow the residual heat in the roasting tray to finish cooking it very gently.»