Heat the oil in a large pan over medium heat.
Add the chopped onions and sauté for 5–6 minutes until golden brown.
Stir in garlic and ginger, cooking for 1 minute until fragrant.
Add turmeric, coriander, cumin, and red chilli powder, stirring well.
Add the beef cubes and sear until browned on all sides.
Pour in the chopped tomatoes and water, cover and simmer for 40 minutes.
Add the potato chunks and cook for another 20 minutes until tender.
Sprinkle garam masala over the curry and stir gently.
Garnish with fresh coriander leaves before serving.
