Step 1 Cook couscous according to packet instructions. Fluff grains with a fork, cover and set aside.
Step 2 Meanwhile, put yoghurt and chopped mint leaves in a small bowl; stir. Place bowl in fridge.
Step 3 Sprinkle both sides of lamb with spice mix. Heat olive oil in a large non-stick frying pan set over medium–high heat. Add lamb and cook for 2–3 minutes per side, or until done to your liking. Remove lamb from pan, cover loosely to keep warm and leave to rest for 5 minutes. Cut cooked lamb into thick slices.
Step 4 Meanwhile, steam, microwave or boil sugar snap peas until just tender; drain. Refresh peas under cold running water; drain again. Place peas in a large salad bowl with remaining ingredients and toss well to combine.
Step 5 Top couscous with za’atar lamb slices, drizzle with mint yoghurt, sprinkle with a little spice and serve with celery salad.