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Mustard roast leg of lamb with pan gravy

Verdict: One of my favourite things to make for a holiday. The leftovers are great in the shepherd's pie.

Serves 6 to 8 · 6 lb bone-in leg · Source: Julia Child's gigot à la moutarde via The View from Great Island, plus thyme and ginger

Ingredients

Coating
  • ½ cup Dijon mustard
  • 4 tbsp extra virgin olive oil
  • 2 cloves garlic, peeled
  • 1 tbsp chopped fresh rosemary
  • 1 tbsp chopped fresh thyme
  • 1 tbsp soy sauce
  • 1 tbsp fresh lemon juice
  • ½ tsp ground ginger
Roast and gravy
  • 6 lb bone-in leg of lamb
  • About 3 cups chicken stock
  • 1 tbsp flour
  • 2 tbsp cold water
  • Salt and pepper

Method

  1. The day before, blend all the coating ingredients in a narrow jar with an immersion blender until thick like mayonnaise, about 30 seconds.
  2. Paint the coating over the whole leg. Wrap tightly in plastic and refrigerate overnight.
  3. Take the lamb out of the fridge about 1½ hours before it goes in the oven.
  4. Set the lamb fat side up on a rack in a roasting pan. Roast on the middle rack at 425°F for 30 minutes.
  5. Drop the oven to 350°F and pour 2 cups chicken stock into the pan. Add more if the pan dries out.
  6. Probe the thickest part, away from the bone. Pull at 130°F for medium-rare, or at 128°F if it is climbing fast.
  7. Rest the leg whole, tented loosely with foil, for at least 20 to 25 minutes. It stays warm for up to an hour.
  8. Gravy: strain the drippings into a measuring cup, let the fat rise, and spoon it off. Add stock to reach about 2 cups and pour into a saucepan over medium heat. Mix 1 tbsp flour with 2 tbsp cold water into a smooth slurry and whisk it in. Simmer, stirring, a few minutes until thickened. Season.
  9. Carve: lay the leg on its side and cut straight down to the bone, across the grain, in ¼ to ½-inch slices. Run the knife along the bone to release them, then flip and repeat. Pour the resting juices over the meat.

Notes

  • The roast often gives very little pan juice. For any real quantity of gravy, make a beef stock gravy and stir the pan juices in at the end. Or make the excellent Bourbon Peppercorn Gravy from venki.com.
  • It cooks faster than the usual 20 to 22 minutes per pound. A 6 lb leg has gone from 70°F at 30 minutes to 115°F at about 70 minutes and been done at 90, so start checking early.
  • Dropping the oven to 325°F late in the roast does not slow it down.
  • Set the probe alarm 10°F early and use an instant-read for the last few degrees.
  • Thyme and ginger are not in Julia Child's original, and the lemon juice is the blog's addition. We like things spiced.