Chop onion, ginger and tomatoes. Add garlic to a mortar pestle and pound coarsely. Or you could use store bough garlic paste.Measure out the spices.
In a cooking pot, add mustard oil till slightly smoky on medium heat
Reduce heat to low and temper hot oil with fenugreek seeds and cumin seeds. Let crackle.
Add chopped onion. Fry the onion on medium-high heat, stirring intermittently till golden brown. Takes 6-8 minutes.
Add chopped ginger and minced garlic along with little water. Fry for 30-40seconds.
Then add the powdered spices. Fry for a minute or so till you smell a nice aroma.
Next, add the chopped tomatoes, tomato sauce (or puree) and sugar. Also add salt. Fry the tomatoes smushing them using back of spoon for 4-6 minutes or until they are soft and oil starts separating. Cook thoroughly to reduce moisture from tomatoes . This slow cooking is very important to develop flavors and color of the paste, please do not rush. Allow the masala to reduce till it acquires beautiful reddish color.Tip - Don't dry out the masala and don't let color change to deep reddish brown but at the same time make sure that masala is bhuna (fried properly). You should be able to a chunky glistening sauce.
Now reduce heat to low and wait for a minute. Add the raw shrimp now. Using a spoon, stir the shrimp around for couple of minutes so that they get coated in the masala.If you added frozen shrimp, no need to add water right now, cover the pot and let cook for 5-8 minutes until the shrimp is opaque. Please adjust cooking time based on kind of shrimp you are using.If you added thawed shrimp or fresh prawns, add ½ cup water then cover the pot. We do need a semi dry masala at the end of cooking.
When the shrimp is just about done, open the lid and add the kasuri methi, amchur and garam masala.If you want to adjust the consistency, add the water accordingly. Let simmer for another 2-3 minutes on low heat till everything comes together.
Garnish with chopped cilantro (coriander leaves). Add some lemon juice if you want.(image 16) Serve warm with indian flatbreads or plain rice.
Notes
Once you add the shrimp, cook on low heat until the end of shrimp. This will make sure that the shrimp wont overcook.
Fresh prawns would be great in this preparation.
If you don't like cumin seeds in the masala, use cumin powder and add it when you add other spice powders.
Fenugreek seeds and kasuri methi (dry fenugreek leaves) add a unique bitter sweet taste to this dish. Unfortunately there are no substitutes. Skip if not available.
You could add some slit or chopped green chillies while cooking the masala for added heat.
Don't use only canned tomato sauce. Chopped tomatoes provide texture to the sauce. You could use canned diced tomatoes.
For enhanced taste, add a teaspoon of ghee at the end of cooking.