Chopp the onions, tomatoes and greenchilie.
Take mixer jar, add chopped onions, tomatoes, green chillies, red chilie powder and pour some water. Grind it smoothly. Heat a pan, add coconut oil and add mustard seeds.
Add the grinded mixture into pan add salt, water and tamarind juice as per the requirement. Cook untill the raw smell and taste go.
Atlast garnish it with curry leaves and coriander leaves.
Serve it with hot idalli, uttappam..