This is a great way to roast a leg of lamb. You may also use a butterflied leg and rub the rosemary blend inside and out - you do not need to score the lamb if you rub the mixture inside. I found this recipe on the net. It is good.
Using a veggie peeler peel the yellow rind from one lemon, do not cut the pith with it Remove pith from this lemon and remove the rind and pith from the second lemon Slice each lemon across into 6 slices.
Drop the zest (yellow saved peel) into a sauce pan of boiling water, blanch 1 minute& remove from water In your blender or food processor process the rosemary leaves, garlic, blanched zest, 1 tbsp oil, lemon juice, season with salt. Process until everything is chopped fine.
Score the lamb leg with small cuts all over and rub the rosemary mixture into the cuts Put the lemon slices on the bottom of your roasting pan and put the lamb on top of them.
Roast lamb for 45 minutes.
Meanwhile scrub the potatoes and cut then in half or quarter them, depending on their size boil for 5 minutes, drain and sprinkle remaining 1 tbsp of oil evenly over them.
Arrange the potatoes around the lamb and continue roasting for a further 50 minutes or until it reaches your desired temp (140°F for med rare, 160°F med & 170°F well done) take out the lamb and let it rest for 15 minutes (I cover it with foil).
Increase oven temp to 450°F.
Arrange the potatoes with the lemon slices in one layer and return to the oven for 5-10 minutes or until the potatoes are golden; toss lemon & potatoes with the chives. Serve along side the roast lamb.