1. In a lined baking sheet coated with foil, place an oven-safe rack (this will help for easy cleanup).
2. Unroll and untie the lamb roast if it is knotted. Trim the top and bottom of the roast to remove thick sections of fat and tendon; make sure to leave a thin layer of fat on top of the roast.
3. In a medium mixing bowl, whisk together all of the ingredients for the Dijon Herb Paste until they blend into a uniform paste.
4. Apply a third portion of the herb paste to the underside of the roast. Fold  the roast back into its original shape and secure it with three strands of kitchen twine in the center and on both ends. Rub the remaining herb paste all over the exterior. Place the roast, seam side down, on a rack on the prepared baking sheet, and set aside to get to room temperature. At the same time, the oven should be heating up.
5. Set up and preheat your oven to 425 degrees Fahrenheit.
6. Allow about 15 minutes of cooking time in the hot oven for the lamb roast. Afterward, turn down the heat to 350 degrees F and cook the leg of lamb roast for 1 to 1 ¼ hour, or until an instant-read thermometer placed in the center of the meat reads 135 degrees F (this is the ideal temperature for medium-rare results – the temperature will still rise as the roast is left to rest before slicing). Place the roast on a cutting board and set aside for 15 to 30 minutes before cutting into it.
7. Using kitchen shears, snip the twine and discard it. Thinly slice the roast (approximately ¼ inches) and put it on a dish. Serve and enjoy your meal.

This is a straightforward and easy recipe to work with, and you may already be able to guess that the results are delicious. The entire cooking duration for this leg of lamb recipe is 1 hour and 45 minutes, including a prep time of 15 minutes, a cook time of 1 hour and 15 minutes, and a 15-minute resting period before slicing.

If you’re interested in more ways to cook a leg of lamb recipes, then we recommend that you try this video recipe.