Heat oil in a large pot over medium heat. Add the sliced onions and sauté until golden brown.
Add the minced ginger and garlic, and sauté for another couple of minutes until fragrant.
Add the mutton pieces and cook until they are browned on all sides.
Add the turmeric powder, red chili powder, coriander powder, and salt. Mix well to coat the mutton pieces with the spices.
Add the chopped tomatoes and green chilies. Cook until the tomatoes are soft and the oil starts to separate.
Pour in the thick coconut milk and stir to combine. Bring the mixture to a boil.
Lower the heat, cover the pot, and simmer for about 45-60 minutes or until the mutton is tender and cooked through.
Sprinkle garam masala over the korma and give it a final stir.
Garnish with fresh coriander leaves before serving.
Serve hot with steamed rice or naan.
Enjoy!
