Mix the marinade and pour over the meat in a bowl. Mix well, then rest in the fridge for minimum 30 minutes, up to overnight.
Slice or chop the onion and red pepper.
Heat a spoonful of oil in a frying pan and sauté them for 5 minutes. Then add the lamb (including the marinade) and stir-fry for 5 minutes until cooked through.
Alternatively, cut the peppers and onion into big chunks and add them to the marinated meat, then thread the lamb and veggies (alternating) onto metallic or pre-soaked wooden skewers. Then barbecue or grill them, turning regularly, until charred.
Serve warm tucked in flatbread with a salad and condiments of your choice.