Finely chop onions and tomatoes or use a food processor.
Heat the oil in a large pan. The oil should be hot but not smoking hot
Sauté onions until brown
Add ginger and garlic and sauté until fragrant
Add a splash of water to prevent the spices from burning in the next step
Add chilli powder, turmeric powder, ground coriander, ground cumin. Fry on low heat until fragrant.
Add chopped tomatoes and salt to help tomatoes soften
Cover for 3-4 min on medium heat
Mash the tomatoes after they have softened and cover again for 3-4 minutes on medium heat. Until it forms a paste
Add sugar
Add cooked prawns and coat with masala
Add water and cook prawns further
Add heavy crème
Add salt to taste.
Add chopped chilli and coriander
Add garam masala