Grind onion, green chilli in a blender to make medium coarse paste. Grind the tomatoes to make tomato purée. Grind cashew nuts with 2 Tbsp water until smooth paste.
Heat 2 Tbsp oil in a pan and add onion paste and salt. Saute it until oil starts to separate.
Add tomato purée and cook on medium flame.
Add red chilli powder, turmeric powder, coriander powder, garam masala powder and salt. Stir and cook for a minute. Add cashew nut paste. Cook for a minute.
Add boiled peas and ½ cup water and cook for 2-3 minutes.
Add paneer cubes and cook for 2 minutes.
Turn off flame and transfer the curry to a serving bowl. Serve with hot flavored rice or roti.