Steps
1. Heat oil in a pan and add mustard seeds; let them splutter.
2. Add sliced onions and green chili, sauté until soft.
3. Add turmeric powder and chili powder, stir for 30 seconds.
4. Add brinjal slices and salt, cook for 5 minutes until slightly tender.
5. Mix vinegar and sugar in a small bowl until sugar dissolves.
6. Pour the vinegar-sugar mixture over the brinjal, stir well.
7. Cook on low heat until brinjal is tender and the liquid thickens into a syrupy consistency, about 10 minutes.
8. Remove from heat and let it cool before serving.