Heat oil in a large heavy bottomed frying pan over medium-high heat.
Add onions. Cook, stirring occasionally, for about 2-3 minutes or until the onions start to brown.
Add green chilies and curry leaves. Saute, stirring, for about 1 minute.
Reduce heat to low. Add turmeric, coriander, and red chili powder. Saute, stirring, for about 30 seconds or until aromatic.
Add tomatoes. Cook, stirring, for about 2-3 minutes or until mushy.
Add cooked beef and the cooking liquid. Stir to combine. Season with salt.
Bring to a boil. Simmer for about 33-4 minutes or until the liquid reduces and the masala coats the beef.
Add garam masala. Stir. Heat through.
Garnish with curry leaves.
Serve with parotta or rice.