In a Dutch oven, heat 2 tablespoons oil over medium heat and brown the onions, garlic, and lamb. Add salt, pepper, turmeric, and cardamom, and sauté for 1 minute.
Pour in 5 cups/1.2l water. Add the kidney beans and the whole limu-omani. Bring to a boil, cover, and simmer for 30 minutes over low heat, stirring occasionally.