1 tbsp olive oil
120 g spinach leaves, washed and dried
20 g flat leaf parsley leaves, chopped
2 tsp Dijon mustard
2 tsp lemon juice
2 boned lamb loin, each weighing about 500g with the flank still attached
4 large fresh whole lamb’s kidneys, membrane and cores removed with scissors (butcher can do this for you if you want)
100 ml red wine
150 ml chicken stock
1 tsp beurre manie, made by mixing 1 tbsp flour with 1 tbsp softened butter to make a paste
Gently heat the olive oil in a small pan. Add the spinach leaves and as soon as they have wilted, tip them into a small sieve and press out as much of the excess liquid as you can. Transfer to a mini food processor and add the chopped parsley, mustard and lemon juice along with a little salt and some black pepper. Blend to a smooth paste.
Preheat the oven to 230C/gas 8. Put the prepared loins of lamb onto a board, skin-side down, and open them out. Season the meat well with salt and pepper and spread half of the spinach mixture down the centre of each one.
Lay 2 kidneys in a line down the centre of each loin and sprinkle with a little more salt and pepper. Wrap the lamb around the kidneys and tie along the length of each one at 3-4 cm intervals with string to make two neat, cylindrical joints. Weigh them and calculate the cooking time, allowing 16 minutes per 450g.
Season the outside of the lamb with salt and pepper, put into a small roasting tin and roast for 15 minutes, then lower the oven temperature to 200C/gas 6 and continue to roast for the remainder of the calculated cooking time – approximately 24 minutes. Remove from the oven, cover with foil and leave to rest for at least 10 minutes.
To make the gravy. Pour the excess fat away from the tin and place the tin on the hob over a medium-high heat and add the red wine. Bring to the boil, rubbing the base of the pan to release all the caramelised juices, and reduce down to 2 tablespoons. Add the chicken stock and strain into a small pan. Boil once more until reduced to a well flavoured gravy. Whisk in the beurre manié and leave to simmer for 2-3 minutes.
Carve each loin across into 6 slices and serve with the gravy and your choice of vegetables.