Heat oil in a large pot or Dutch oven over medium-high heat. Sear the beef until browned on all sides, then remove and set aside.
- In the same pot, sauté the chopped onion for about 5 minutes until softened. Add garlic and ginger, and cook for 1–2 minutes until fragrant.
- Stir in tomato paste, curry powder, cumin, coriander, turmeric, and cayenne pepper. Cook for 1 minute to bloom the spices.
- Return beef to the pot and add coconut milk and beef broth. Stir well to combine.
- Add the diced sweet potatoes and season with salt and black pepper.
- Bring to a gentle simmer, reduce heat to low, cover, and cook for 1.5 to 2 hours until beef is tender and sweet potatoes are soft.
- Meanwhile, prepare garlic naan by brushing with melted butter or oil and minced garlic. Toast in a skillet or oven until warm and slightly crispy.
- Serve curry hot, garnished with chopped cilantro, alongside garlic naan.