Add the remaining oil to the kadai on medium heat and let warm up.
Temper the hot oil with bay leaf, cinnamon stick, green chillies, chopped ginger & garlic paste. Fry everything for a minute or so until the raw smell disappears taking care not to brown anything.
Add the finely chopped onions next. Sauté for 6-8 minutes on low medium heat until they turn golden brown.
Sprinkle the kashmiri red chili powder, turmeric powder, coriander powder, and half of the prepared kadai masala. Mix well and cook for a minute.
Now add the finely tomatoes and tomato sauce. Add salt and while regularly stirring, cook the tomatoes until the oil separates from the masala. Don't dry out the masala.
Lower the heat and add the marinated shrimp to the kadai. Mix well, coating the shrimp with the masala.
Let the shrimp cook on low heat for next 3-5 minutes or until they appear orange and are fully cooked. You could cover the kadai if you wish. If you want a slighly thin sauce, add ½ cup of warm water right now.
Once the shrimp is cooked through and appears opaque, sprinkle the remaining kadai masala, garam masala powder and kasuri methi. You can also add bit of lemon juice at this stage for added tang. Mix well.
Then add the onion and bell pepper chunks. Cook everything on low heat for 2-3 more minutes just to warm up the vegetables. Switch off the stove.
Garnish with cilantro. Serve warm.