Heat oven to Gas Mark 7, 220°C (425°F).
To make the stuffing:
Heat the butter in a frying pan over a medium heat. Add the onion and cook over a low heat, stirring, until the onion has softened, about 10 minutes. Add the garlic and cook for another minute. Stir through the chopped rosemary leaves, apricots and spinach. Stir to combine. Leave on the heat for another couple of minutes until the spinach wilts. Remove to a mixing bowl. Add the breadcrumbs, lemon zest and salt and black pepper.
While the stuffing is cooling prepare the pork. Place the meat on a chopping board. Run a sharp knife across between the bones and meat to separate them and make a pocket for the stuffing. Don’t cut all the way through, leave the bone and meat connected for about 3cm at the base of the bones.
When the stuffing has cooled, press it into the gap between bones and the meat. Tie up with string all the way along to hold the stuffing in. Use foil to cover any exposed stuffing as it will burn in the hot oven. Place the chopped onion and carrots in a roasting tin and place the joint on top. Season the joint with salt and pepper and cover with tin foil. Place in the preheated oven.
Allow to cook for 30 minutes per ½kg. After the first 45 minutes reduce the heat to Gas Mark 6, 200°C (400°F). To be absolutely accurate use a meat thermometer. For the last half hour remove the tin foil. When the meat is cooked remove from the oven, transfer to a chopping board, cover loosely with tin foil and allow to rest for 20 minutes.
To make the gravy: Stir the flour into the juices in the roasting tin. Place over a medium heat and continue stirring with a wooden spoon. Gradually add in the stock or water and stir until it thickens.
Taste and season. Put through a sieve into a warmed gravy boat. Discard the vegetables that were cooked in the roasting tin.
To serve: Slice the pork and serve with roast potatoes and honey glazed carrots and parsnips.
To cook the carrots and parsnips: Roughly chop some cleaned carrots and parsnips, then toss them in a little olive oil and honey and season with salt and pepper. Roast in the oven for 30-40 minutes until tender.