Recipe by Chef Laura Kenny, Real Food Catering
In a food processor combine all ingredients and pulse until mixture is at sauce consistency. Season to taste with salt and pepper.
Whisk first 3 ingredients and 1 cup water in a small bowl until sugar and salt dissolve. Place onion in a jar; pour vinegar mixture over. Let sit at room temperature for 1 hour.
Preheat oven to 400°F. Season lamb well with garlic, oil, salt and pepper. Place the lamb on a wire rack on an oven-proof tray under the oven broiler. Broil 5-7 minutes on each side. Turn oven temperature down to 325°F and roast 1 hour, or until desired doneness.
For medium-rare, pull from oven at 135°F (it will continue to cook 3-5 degrees after removed from oven).
Slice thinly and serve with Chimichurri Sauce and Pickled Onions.
USDA recommends lamb reach an internal temp of 145F and rest for 3 minutes.