I have a deep love of lamb, with its delicious, gamey flavor and it is perfect to serve for a spring dinner, particularity for Easter. In the past, I’ve done yogurt-marinated butterflied leg of lamb on the grill to superb results and wanted to try a similar preparation on bone-in leg of lamb, available through South Mountain Creamery and using their delicious Whole Milk Yogurt. I chose to roast it so I could control the internal temperature of the meat a little better and the results were really delicious.
Using a meat thermometer is very important as you do not want to overcook your lamb. For me, I really like lamb on the rare side of medium rare so I cooked it to 140°, but I even would have preferred 135°. Prior to making this recipe, I did a bit of research on proper cooking temperatures for roast lamb, with some recipes recommending 160°(!) and the USDA recommending a minimum of 145°. Do what feels right for you, but I’m comfortable with the lower amount, particularly when cooking for a smaller crowd and you typically eat from the outside of the meat in, and when eating leftovers, those more rare interior slices of meat will cook further upon reheating. And rare to medium rare lamb just tastes so good!
The other note I’ll make is about time in the oven. Recommended cooking times I found for roasting a bone-in leg of lamb called for 15-20 minutes of cooking time per pound of lamb when the meat is pulled out of the refrigerator an hour ahead of time. With a 4-pound leg, I estimated it would take about a hour to cook, but was probably closer to 1 1/2 hours in my oven, which reiterates that a good meat thermometer is really necessary.
Yogurt-Marinated Leg of Lamb
- 2 cups South Mountain Creamery Whole Milk Yogurt
- 1 tablespoon fresh rosemary, minced
- 1 tablespoon fresh oregano, minced
- 2 teaspoons salt
- 8 garlic cloves, thinly sliced
- 1/2 teaspoon pepper
- 4 pound South Mountain Creamery Leg of Lamb
Marinate the lamb 24 hours before you plan to roast it. Mix the herbs, salt, pepper and garlic in a bowl.
Pour the yogurt into a resealable plastic bag, then add the herbs. Massage the contents to completely mix everything together. Add in the leg of lamb, massage it again to completely coat the meat, then transfer the bag to the refrigerator. The lamb should marinate for 24 hours to help tenderize and flavor the meat.
Remove the lamb from the bag, wipe off any excess yogurt with a paper towel, and place it on a wire rack over a baking sheet. To help ease clean up, spray the wire rack with cooking spray and line the baking sheet with parchment. Let the lamb sit for at least an hour (up to two hours) before you want to put it in the oven to let it come up to room temperature.
Preheat the oven to 400°. If you have one, insert a meat thermometer with an external monitor into the thickest part of the meat, without hitting the bone. Season the outside of the lamb all over with salt and pepper. Place the baking sheet on a rack in the middle of the oven and cook at 400° for 20 minutes, then reduce the temperature to 325° and continue cooking until the lamb reaches 135°-140°. The total cooking time should be 15-20 minutes per pound of meat (although see my caveat above).
Let the meat rest for 15-20 minutes before carving. Serve the slices with some Rosemary Salt on the side for your guests to sprinkle over the meat.