Lamb korma is a rich, mild Mughlai curry where tender lamb is simmered in a yogurt-nut sauce with aromatic spices. High in protein and deeply satisfying, it's a beloved family dinner staple.
In a large Dutch oven or heavy pot, heat canola oil over medium heat. Add the sliced onions and saute, stirring frequently, until deep golden brown, about 15–20 minutes. Remove half of the onions and set aside for garnishing.
Add minced garlic and grated ginger to the pot; cook for 1–2 minutes until fragrant. Stir in the ground coriander, cumin, turmeric, and black pepper. Saute for 1 minute, ensuring the spices do not burn.
Increase heat to medium-high. Add lamb pieces in a single layer and sear until lightly browned on all sides, about 6–8 minutes, turning occasionally for even color.
Blend cashews with half of the yogurt and 1/4 cup water in a blender until very smooth. Pour this mixture into the pot, along with the remaining yogurt. Add cinnamon stick, bay leaf, garam masala, and salt.
Reduce to low heat. Cover and simmer gently for 1.5–2 hours, stirring occasionally, until lamb is fork-tender and sauce is creamy and thick. Adjust salt if needed. Remove bay leaf and cinnamon stick before serving; garnish with reserved fried onions.