Heat oil in a pan over medium heat and add cumin seeds.
Once fragrant, add onions and sauté until golden brown.
Stir in garlic, ginger, and green chili, cooking for another minute.
Add ground beef and cook until browned, breaking it apart with a spoon.
Mix in chopped tomatoes, turmeric, ground coriander, red chili powder, and salt. Cook until tomatoes soften.
Add diced potatoes and pour in water. Cover and simmer for 15-20 minutes until potatoes are tender.
Sprinkle garam masala, stir, and let it cook for another minute.
Garnish with fresh cilantro and serve hot with rice or flatbread.