Prepare lamb by removing from packaging and any netting. The boneless lamb I buy is butterflied, which makes it easy to unroll and marinate.
I marinated this one in: Whats that there sauce (Worcestershire Sauce), Original Allegro Marinade, Spicy Brown Mustard, Garlic Powder, Black Pepper and just a touch of Honey.
Let sit on counter, loosely covered for about an hour until room temperature. This will ensure even cooking.
In the bottom of a stoneware bowl I put 2 sliced medium onions, 4 medium parboiled red potatoes (cut in half), several mushrooms sliced in half and a few sprigs of fresh rosemary. No need to add liquid, the vegetables and meat will create pan juices.
I used high temp cooking bands to truss the leg back up and placed a round cookie rack over the vegetables.
Preheat oven to 450 degrees, sear meat for 15 minutes. Lower temperature to 325, roast at 20-25 minutes per pound. We like ours medium rare with reads 145 degrees on a meat thermometer. *Note meat’s temp will continue to rise up to 5 degrees after removal from the oven.
While the meat was “resting” lamb does get tired in the oven, I turned the temp up to 510 and put the vegetables back in to finish roasting and caramelize.