For the red onion compôte, heat a heavy bottomed pan over a medium heat, add the oil and then the sliced onions. Fry gently for 2-3 minutes, until they start to soften, then add the salt, the pouch of pepper and the dried apricots. Fry the mixture gently for 5-6 minutes until the onions are soft.
Add the lemon zest and juice, followed by the lamb stock and cook slowly for one hour until the mixture has a compôte consistency.
Meanwhile, for the stuffed saddle of lamb, preheat oven to 180°C/350F/Gas 4.
With a sharp knife, remove the outside skin from the lamb. Then cut down the middle of the lamb saddle, down to the bone, and remove the loin from the bone, keeping the fat attached.
Now carefully remove some of the fat, according to your taste, and flatten the outside skin with a meat baton.
Heat a frying pan, add a tablespoon of olive oil, then add both types of spinach and mix with the garlic studded fork until the spinach has wilted. Drain the spinach onto kitchen paper and squeeze out any excess liquid.
Heat a frying pan, add another tablespoon of olive oil, and the chopped kidney and gently fry for one minute before adding the red pepper, olive and cooked spinach. Season with salt and pepper and set aside to cool.
Place the stuffing mixture onto the skin of the lamb and fold it over the meat.
Wrap the stuffed lamb in the crepinette and tie with string.
Heat an oven-proof frying pan over a medium to high heat, add a tablespoon of olive oil and add the lamb, wrapped in crepinette. Fry gently to for 2-3 minutes until golden-brown. Add the red onion halves and transfer the pan to the oven for 15 minutes. Remove from the oven and set aside to rest for 10 minutes.
To serve, carve the lamb into thick slices. Spoon the red onion compote into the centre of the serving plates and place the lamb on top. Peel the red onion apart into petals and scatter around the plate. Finish with a few leaves of baby spinach.