1. Generously season lamb pieces with salt and pepper. Heat 2 tablespoons oil over medium-high heat in Dutch oven until just beginning to smoke. Place half of lamb in the pot and cook, without stirring, until well browned, about 2 minutes. Turn and continue cooking until browned all over, another 2-4 minutes. Transfer to a plate and repeat with remaining lamb. When second batch of meat is browned, remove from pot and set aside.

2. Combine garlic and ginger in a small bowl, stir in one teaspoon of vegetable oil and set aside.

3. Add 1 tablespoon oil to the now-empty pot. Add peppercorns, cloves, bay leaves and cardamom, and stir for two seconds. Immediately add in the onions and a pinch of salt. saute onions, stirring vigorously to bring up the browned meat from the bottom of the pot, until beginning to brown, about 5 minutes. Push onions to the side of the pot, add garlic-ginger-oil mixture and push down with the back of a wooden spoon until fragrant, about 30 seconds. Stir garlic-ginger mixture into the onions. Add the cumin, coriander, fenugreek and cayenne, and stir for 5 seconds. Add meat and any accumulated juices and stir to combine.

4. Add in 1 tablespoon of the beaten yogurt and stir until well combined. Repeat with remaining yogurt, one tablespoon at a time. Add spinach, one handful at a time, stirring until beginning to wilt before adding another handful. Once all the spinach is incorporated, add a pinch of salt, and stir until spinach is completely wilted. At this point, the stew may seem too dry; don?t worry - it will thin out as moisture escapes the spinach.

5. Cover pot tightly, reduce heat to lowest possible setting and cook gently until meat is tender, about 70 minutes.

6. Remove lid and stir in the garam masala. Increase heat to medium and cook for 5 to 10 minutes, until most, but not all, of the water evaporates and sauce thickens. Season to taste with additional salt, and serve over basmati rice.