In a blender, combine the oil, onion, garlic, parsley, cumin, lemon zest, lemon juice and salt and puree until smooth. Transfer the marinade to a resealable plastic bag and add the lamb. Seal and refrigerate for at least 6 hours or preferably overnight.
Light a grill or preheat a grill pan. Drain the lamb, shaking off the excess marinade. Thread the lamb onto 4 long skewers. Grill over high heat, turning occasionally, until lightly charred, about 5 minutes for medium-rare meat. See cooking temperatures below.
Sesame Sauce:
Add yogurt, tahini and lemon juice to a large bowl and stir to combine. Season with salt and pepper, to taste.
In a small skillet, toast the sesame seeds and cumin seeds until fragrant.
Spread the sesame sauce on a large serving plate and drizzle with the olive oil. Sprinkle with toasted seeds and parsley. Arrange the grilled lamb skewers on top. Serve.
Notes
Cooking temperatures
Rare: 115ºF – 124ºF (very pink inside)
Medium rare: 125ºF – 135ºFF (bright pink inside)
Medium: 136ºF – 144ºF (light pink inside)
Medium well: 145ºF – 154ºF (barely any pink left)
Well done: 155ºF (no pink)
Tips and tricks
The lamb should be marbled with fat, but if you have a particularly fattier cut, trim off any excess before cutting into cubes.
Plan ahead so there’s plenty of time to marinate the lamb. The longer the lamb marinates, the better the flavor (overnight is best).
Remove the marinated lamb from the fridge 15 to 30 minutes before grilling so the pieces cook evenly.
If you’re using bamboo skewers, soak them in water for 30 minutes to keep them from burning on the grill.
Grill lemons for serving while you grill the lamb. Cut the lemons in half and grill them cut side down until lightly charred and softened.