- In a large nonstick skillet over medium heat, heat 1 tablespoon oil. Season lamb with salt and pepper. Cook, in batches if necessary, until browned on all sides, about 6 minutes.
- Transfer browned lamb to slow cooker insert. Add remaining 1 tablespoon oil to pan (if necessary); add onion, garlic, ginger, cumin, coriander, cinnamon and cayenne.
- Cook until softened, about 8 minutes.
- Add broth and tomatoes; bring to a boil.
- Add mixture to slow cooker along with chickpeas and raisins.
- Cover and cook on low for 5 to 6 hours, or high for 3 to 4 hours.
- Remove lid; stir in chopped greens until wilted, about 1 minute. Serve with whole wheat couscous and a dollop of Greek yogurt.