This dish uses lamb medallions cut from the loin. A dry marinade, also known as a dry rub, is an excellent way to add flavor to meat or poultry that will be grilled or roasted. Be sure to use unsweetened coconut milk.
In a small bowl, thoroughly mix the coriander, onion powder, garlic powder, cumin, chili powder, turmeric, nutmeg, salt and black pepper.
Trim all excess fat off the lamb medallions and rub them with the spice mixture. Marinate in a 9-inch by 13-inch baking dish in the refrigerator for at least 2 hours but no longer than overnight.
Meanwhile prepare the salad. In a medium bowl, toss the cucumber with yogurt and scallions. Refrigerate until ready to serve.
In a cast-iron skillet, heat the canola oil over medium-high heat. Remove the medallions from the marinade and cook for 2–3 minutes on each side, according to desired doneness. Remove from the skillet, set aside to cool for 5 minutes and then season with salt and pepper. Discard any excess oil in the pan, leaving any spices and bits of lamb stuck to the skillet.
Meanwhile, combine the coconut milk and water in a small bowl. Using a spatula, scrape the spices and bits of lamb from the sides and bottom of the skillet. Add the coconut milk mixture and bring to a simmer, stirring to incorporate the pan scrapings.
To serve, place one-quarter of the cucumber salad on each plate. Place one lamb medallion beside each salad and one-quarter of the coconut sauce over one.