Unroll the rolled lamb if alreasy tied and place flat on a chopping board.
Peel the onion, garlic and shallot.
Finely mince the garlic, chop the shallot and cut the onion into rings of about a centimetre of just less than half an inch.
Heat the butter over amedium heat in a small frying pan and add the chopped shallot.
Cook for a few minute s to soften the shallot without colouring then add the garlic and cook for 1 minute. Turn off the heat.
Remove the rosemary and thyme leaves from the woodystem and finely chop along with the parsley.
Put the fresh breadcrumbs in a bowl and add the herbs, garlic and onion mixture and seasoning.
Lay 3 or 4 pieces of string on the chopping board and place the first piece of lamb over the top. The short end of the lamb should be facing you.
Place half of the stuffing mix on the lamb. I find it's easier to use a spoon to add the stuffing and then use the back of the spoon or the palm of your hand to press it into an even layer.
Repeat with the other piece of lamb.
Carefully roll the lamb up and tie the string.
Place the onion rings in the bottom of the roasting dish and lay the meat seam side down. Add the hot water from the kettle.
Season the lamb with the remaining salt and pepper.
Cover the dish with foil.
Preheat the oven to 160 C / 310 F / 140 FAN / Gas 2.5 and roast for 2 hours.
Increase the temperature to 180 C / 350 F / 160 FAN / Gas 4, remove the foil and cook for a further 30 minutes to brown the meat.
Place the lamb on a plate and cover with foil to keep warm.
Remove all the fat from the dish except a tablespoonful then add the hot lamb stock and heat on the hob until bubbling over a medium heat.
Use a wooden spoon to loosen any grungy bits stuck to the bottom and check the seasoning.
If you would like to thicken the gravy, combine the cornflour with the water and stir in to the gravy for a minute.
Cut the stuffed breast of lamb into thick slices and serve with the gravy