Preheat the oven to 170C/150C fan
Heat the olive oil in a small frying pan and saute the onion and garlic until soft and starting to brown (8 - 10 minutes).
In a bowl, combine the cooked onions and garlic with the rest of the stuffing ingredients. Season with a little salt and some black pepper.
If your breast of lamb is rolled and tied, cut off the strings and unroll it. Season both sides with salt and pepper then leave skin side down.
Note: you'll probably need another pair of hands to help with this stage.
Spread the stuffing all over the opened up lamb, then re-roll (starting from a short side) as tightly as you can. Re-tie with string.
In a large pot or frying pan, heat the olive oil. Add the stuffed and tied lamb and brown all over.
Transfer the lamb and any juices from the pan to a large lidded casserole or roasting tin. Put the lid on or cover tightly with foil if you have no lid.
Slow roast in the oven for 2.5 hours or until the lamb is very tender.
Tip: if you want to make roast potatoes to accompany the lamb, remove some of the fat from the roasting dish partway through the cooking.
To crisp the skin, turn the oven up to high and cook for a further 10 minutes.
Remove the lamb, wrap in foil and rest for a minimum of 10 minutes before slicing and serving.
While the lamb is resting, take the cooking juices plus any of the stuffing that's fallen out and put into a saucepan, including about 1 tbsp of the fat.
Heat over low to moderate heat, then add the flour and stir well, making sure you scrape up any bits of stuffing. Cook for 5 minutes.
Gradually add the stock, stirring well after each addition. Allow to thicken, bubble and reduce (approx 8-10 minutes).
Use a stick blender to whizz to a smooth sauce. Check the seasoning and add more salt and pepper if needed.
Recipe adapted from Delicious magazine and TheGreekFood.com