Prepare a smoker with wood or pellets (preferably hickory or apple wood) to 250℉/121℃.

Prepare a bowl, add black pepper, salt, dried oregano, cumin powder, garlic powder and stir well. Set aside.

Trim any loose hanging fat. Don’t trim the fat cap—during the low slow cooking, it will render, adding flavor to the lamb. Score the fat cap in a diamond pattern to expose the meat (do not cut through the meat completely!). This helps to render the fat, and will allow the herbs and spices to penetrate to the meat.

Brush an even layer of yellow mustard on the surface of the lamb leg, sprinkle the seasoning powder evenly on the surface of the lamb leg, and stuff the garlic and rosemary into the cuts.

Select lamb→ roast→ leg in the parameters list. Set the target temperature to 140℉/60℃.

Transfer the Lamb Leg into your preheated smoker, then securely close the lid.

To begin the process, simply press the start button on your phone.

Carefully remove the leg and place it on a heat resistant surface. Let it rest for at least 10 minutes.

Carefully remove the probe.

Slice and serve!