Cook the Beef:
In a large skillet over medium heat, add oil and ground beef. Cook until browned, breaking it up as it cooks. Drain excess fat if needed.
Sauté Aromatics:
Add diced onion and cook for 3–4 minutes until soft. Stir in garlic and ginger, and cook for another 1–2 minutes until fragrant.
Add Spices:
Sprinkle in curry powder, cumin, coriander, turmeric, and chili powder. Stir to coat the meat and toast the spices for 1 minute.
Add Tomatoes:
Pour in the diced tomatoes (with juices) and water or broth if the mixture seems dry. Stir well and bring to a simmer.
Simmer and Finish:
Simmer for 10–15 minutes, uncovered, until the sauce thickens. Stir in frozen peas in the last few minutes if using. Adjust seasoning with salt and pepper.
Serve:
Garnish with chopped cilantro. Serve hot over rice or with warm naan bread.