I have a half leg of lamb on the bone that weighs about 1.2kg. I have a recipe for slow roasted with garlic and rosemary. It says it should be in the oven at 120°C for three hours covered with foil, then turn it over and cook covered for another hour. Then uncover, pour red wine over and cook at 150°C for a further two hours. Adding more water if it dries out. I'm guessing I should reduce the cooking time slightly as the recipe is for a 1.8kg leg. I'm not sure how much I should reduce the cooking time. It's obviously not going to be pink but it should still be really tender and fall off the bone. Probably when it goes in at 120 it won't matter as the temp is so low. Should I just reduce the amount of time it is in the oven at 150
CraigC
Guru
I'd find a recipe that gets you a rare to med-rare roast. I want my lamb pink on the inside.
ElizabethB
Guru
DITTO
I have a boneless leg of lamb in the freezer and will definitely research recipes for a medium rare roast. I love rack of lamb and always cook it medium rare.
ElizabethB
Guru
I can't say because I have never cooked that cut.
GadgetGuy
(Formerly Shermie)
I've done one once, but it was some time ago. I was a small one. A large one is way too big for me!! 
To be honest you really don't have to worry - it will be fine whatever size it is. This recipe is slow cooked on a low temperature. Shoulder of lamb is fatty and it won't dry out and can cook longer than the recipe states.
rascal
Forum GOD!
epicuric
Legendary Member
You will struggle to cook a shoulder of lamb medium rare in a conventional oven, without it being really tough. It needs to cook for a long time to ensure tenderness, and most ovens struggle to stay below 100 deg C, which will result in well done meat. Aim for as low a temp as you can, 100 deg C is fine, for say 6 hours with the meat covered. By way of illustration, I do mine at 55deg C for 12 hours, but that's not in a conventional oven. Forget the faffing around turning it over and changing temperatures - sounds like a food journalist recipe. Shoulder of lamb is very forgiving at low temperatures, so you really can't go wrong! Agree with the garlic, rosemary and red wine, plus anchovies and cooking on a trivet of vegetables works really well. You may want to brown the meat after cooking, and would recommend resting it, covered for 30 mins before carving.
Burt Blank
Legendary Member
Low and slow in the oven my Greek way. Make slits all over the shoulder and stick in bits of garlic and oregano. juice a few lemons reserve juice and use the empty skins to form a trivet in the roasting pan. Place the shoulder on the trivet and first massage in olive oil then lemon juice. Season hard with salt and pepper. Surround with medium sized peeled potatoes ( absorb fat ) Cover with foil (dull side up ) and bake in a low oven till you can stick a teaspoon in it easily. Remove foil , spin the spuds to fat soaked side up. Brown in hot oven. Serve in the baking tin as it will fall apart if you try to transfer it. Courtesy of my great mate and Kalamata cooking legend Captain Niko G