Combine the honey, balsamic vinegar, olive oil, mustard, rosemary, ground black pepper, salt, lime juice and garlic. Mix well and apply to the lamb. Cover and marinate in the refrigerator overnight.
Take the marinated leg of lamb out of the refrigerator about an hour before cooking so it comes to room temperature. This allows for faster, more even cooking.
Heat the oven to broil. Set the lamb in a rack inside a roasting pan.
Broil the lamb for 5 minutes or until the top of the lamb leg looks seared and browned. Make sure to position the oven rack so that the top of the meat is a few inches from the broiler element.
Flip the lamb over and broil the other side for 5 minutes or until the other side is seared and browned. Remove the roast from the oven and set aside.
Turn off the broiler and set the oven temperature to 325°F. Reposition the oven rack to the middle of the oven. Brush approximately half of the remaining marinade on to the roast and reserve the rest to use later.
Tent the pan loosely with foil to keep the garlic and rosemary from burning. Put the lamb back in the oven and cook at 325°F for one hour.
After an hour in the oven, remove the foil and take the temperature. The lamb is ready (medium-rare to medium) when the temperature is 135°F (or above).
If needed, continue cooking the lamb uncovered until done. Check the temperature every 20 minutes until it reaches your preferred temperature.
Let the lamb rest for at least 15 minutes before carving.
To make sauce
Place all roast drippings into a small saucepan. Add 1 cup of water and the remaining marinade.
Add 2 tablespoons of honey, 1 teaspoon of salt and the juice from 1/2 a lime into the saucepan.
Bring mixture to a boil then reduce heat to simmer.
Dissolve 1 tablespoon of tapioca starch into 1/4 cup of cool water. Pour into saucepan and continue to stir while simmering. Simmer for 5-10 minutes.
Serve sauce hot in a gravy boat. Pour on top of lamb roast slices and tastes delicious on top of rice, potatoes or veggies.
Omit mustard from this recipe to make it mustard-free.
Check here for lamb cooking time and temperature chart.
Once upon a time I cooked and ate whatever I wanted to without giving ingredients a second thought ... then I became a mother. When my eldest son was 5 months old, we discovered the hard way (a visit to the ER) that he had a severe allergy to milk. A few months later we discovered he was also anaphylactic to eggs, peanuts, tree nuts, wheat and chicken. My initial reaction: PANIC!! But with time, practice, and many errors, I now enjoy cooking allergen free food and goodies so that my 3 children, 2 of which have multiple food allergies, can enjoy the same treats that other kids are eating.