Cut the beef into medium pieces and wash it thoroughly.
Cook the beef in a pressure cooker with onion, ginger, green chilly, salt and curry leaves. Allow it to rest until the pressure goes off, keep aside.
Heat oil in a pan & add oil, add the paste (garlic, cumin seed, mustard seed, pepper) when it turns light brown, add onion, ginger, green chilly and curry leaves. Saute until the onions turn translucent.
Add the turmeric powder, half garam masala powder, chilly powder and saute till raw smell goes off. Next, add sliced tomato & mix well.
Add some stoke from the boiled beef. cook for few minutes till the tomato is well done. For gravy, add some hot water.
Once it starts to boil, add boiled beef and mix well. Next, add the remaining gram masala powder & salt to taste. Cook on low for 5 minutes.
Next, add some vinegar to taste. Mix well and cook on low flame till the gravy thickens.