Finely chop onions, tomato, and garlic.
Lightly crush the garlic. Marinate the chicken pieces with the crushed dry chillies, vinegar, garlic and salt.
Mix well, and let it sit for an hour. You can skip the marination, but to get all the great flavours of garlic, you SHOULD marinate.
Heat some oil in a thick-bottomed pan. Add chopped onions and cook on a medium flame while stirring occasionally.
Sweat the onions till they are tender and cooked well. When the onions start turning brown, add the chopped tomatoes, and cook further.
Cook on a low flame till the onion and tomato mix reach a thick paste like consistency. Add salt, sugar, and 3 tablespoons of water.
Combine well. Switch off when the water start to disappear.
Transfer the contents to a bowl.
Use the same pan, add a little oil, and braise the marinated chicken on a high flame.
Stir occasionally and fry for a couple of minutes. Lower the flame, and cook with the lid closed for about 10 minutes.
Open the lid, add the onion-tomato paste back to the pan, mix well, and cook on a low flame.
Add salt if required. Cook till chicken pieces is evenly coated. Add the chopped green chillies, and a tablespoon of finely chopped spring onions.
Combine well. Cook for a couple of minutes, and switch off.
Garnish with spring onions, and serve hot.
You can enjoy this garlic chicken on its own, or with some fragrant rice.
Recommendation: For best results, serve 4-5 hours after cooking. This will help the flavours to develop further. Heat it up in a pan just before serving.