In a large bowl combine olive oil, lemon juice, minced garlic, ground cumin, ground coriander, smoked paprika, ground black pepper, kosher salt, and yogurt (if using). Whisk until smooth and homogenous.

Marinate

Add the lamb cubes to the marinade and toss thoroughly to coat every piece. Cover and refrigerate for at least 1 hour and up to 6 hours. For best flavor without over-tenderizing, avoid marinating longer than 8 hours because of the yogurt/lemon.

Skewers & Finish

Prepare vegetables and skewers

If using wooden skewers, soak them in water for 30 minutes to prevent burning. Cut the red onion and bell pepper into pieces similar in size to the lamb cubes so everything cooks evenly.

Assemble brochettes

Thread lamb pieces onto skewers, leaving a small gap between pieces for heat circulation. Alternate lamb with onion and pepper pieces if desired. Aim for 4–6 lamb cubes per skewer depending on skewer length.

Preheat grill or pan

Preheat an outdoor grill to medium-high (about 400–450°F / 200–230°C) or heat a heavy cast-iron grill pan over medium-high heat. Lightly oil the grill grates or pan.

Cook the brochettes

Place skewers on the hot grill or pan. Cook for about 3–4 minutes per side, turning to brown all sides, for medium-rare to medium (internal temperature 130–140°F / 55–60°C). If you prefer medium-well, cook a bit longer until 150°F / 65°C. Total cook time will be about 10–12 minutes depending on heat and cube size.

Rest and finish

Transfer cooked skewers to a plate and let rest for 5 minutes to let juices redistribute. Sprinkle chopped parsley over the brochettes and serve with lemon wedges to squeeze over just before eating.