You need a good roasting pan. In it put some olive oil, pepper, Worcestershire sauce, HP, or even a beef seasoning like liquid Bovril, and/or what ever spices you like, and 1/2 a cup of water.
If the roast has the string like mesh wrap, leave that on to hold the shape. Season with some pepper, and rub in some Worcestershire sauce, HP, or even a beef seasoning like liquid Bovril.(I know, beef flavor on lamb sounds weird, but it works.)
Peel 2-3 large potatoes per person, cut into 2-3” chunks, rinse with water to remove surface starch.
Dump the potatoes into the roasting pan, and mix with your hands to spread the liquid seasoning.
Move the potatoes to the edge of the pan, and place the roast in the center “Fat side down”.
Place in the center of a 350F oven, uncovered. Your 2 1/2 lb piece should cook for at least 2 1/2 hours. Possibly longer.
The only trick is to make sure you have a bit of liquid in the bottom of the pan at all times. Don't let the bottom burn. Add more water at any time when/if needed. Feel free to stir the potatoes and baste every thing a bit if you want, but no more than once an hour.
If there are any left over roasted potatoes, trust me, you won't mind.
I'm sorry, my dear FRiend - but no way am I going to pot roast a leg of lamb and that is what this recipe does. I want my lamb rare - nice and pink in the middle. A 2 1/2 lb boneless leg will take about an hour to an hour and a quarter - TOPS.
Jusst told mrs p6 to pick up another or two when she is out tomorrow. Your stew sounds fantastic...like what I grew up with. With the roasts vacum packed they should be good. I might make my scotch broth from the early roast leftovers and freeze it. Great for a cold February or March!