Heat the oven to 180C/160C fan/gas 4. Put a large, lidded, flameproof casserole over a high heat and add the oil. Once hot, add the spring onions and cook for a minute or so on each side until golden, then remove to a plate with tongs. Do the same with the asparagus. Set aside for later.

Season the chicken, then add to the pan breast-side down and cook for about 3 minutes until the skin is golden. Turn it over and reduce the heat to medium. Add the garlic to the pan, stirring it around the chicken rather than on top. Pour in the wine and bubble for a few minutes until reduced a little, then pour in the stock. Bring to the boil, then add the lid and pop in the oven. Roast for 1 hour 10 minutes.

While the chicken roasts, put half the watercress (using up the stalkier ends rather than the leaves where possible) in a blender with the lemon juice and zest, and whizz to a paste.

Take the pot out of the oven, then stir the orzo, the whizzed watercress mixture and the charred vegetables into the liquid around the chicken. Cover again and return to the oven for 15 minutes.

Remove the lid and leave to stand for 15 minutes – this gives the chicken a chance to rest and the orzo will finish absorbing the liquid.  Check the seasoning and stir in the remaining watercress just before serving.