irishgirl: That sounds good. I’ll have to try it with leftover lamb. (If Trader Joe’s ever gets leg of lamb back in stock!)
To the OP: Trader Joe’s pre-seasoned frozen leg of lamb is super-easy. Just thaw the roast and cook it in a 400ºF oven for an hour. This will be rare (but not too rare), so cook it longer if you like it better more cooked. Personally, I like it rare. Remove the roast to a plate. Add some flour to the drippings and stir it into a paste. Toast the paste in the pan. Be careful not to burn it, but if you undercook it your gravy will taste floury. Add water, stir frequently, and reduce it to the desired consistency. You’ll want enough gravy for leftovers. Serve with vegetables and mashed potatoes. Trader Joe’s leg of lamb is pre-seasoned with garlic and rosemary. You can get a leg of lamb elsewhere and season it yourself if you like.
Leftover leg of lamb: Use it for shepherd’s pie. Slice the roast and run the slices through a meat grinder. (I have a chrome-plated cast-iron one I bought at a garage sale for $5. you can buy them new at Bed, Bath & Beyond or Amazon.com for about $30.) In a large bowl mix the ground lamb, a package of frozen mixed vegetables, and the leftover gravy. Put into a baking dish and top with your leftover mashed potatoes. Bake in the oven (375º to 400º) until the potatoes brown a bit. Alternatively, you can top it with colcannon if you’d made that instead of mashed potatoes.
Colcannon: Chop up a bunch of kale. I remove the stems first and just use the leafy part. Boil in water until tender. Make a batch of mashed potatoes. Drain the kale and mix it into the mashed potatoes, adding salt and pepper to taste.