Wash all the cilantro and trim the ends of the stems. In a skillet over medium heat, add the oil. When hot, add all the cilantro and cook, stirring occasionally until it turns dark green. This should take a few minutes. Add the dried fenugreek you have strained out of the soaking water and cook another minute or two.
Remove to a bowl and set aside.
In another bowl, mix the shrimp with the oil, salt, pepper and chili and set aside.
In the skillet, melt 2 tbsp butter over medium heat and add the onion and a pinch of salt. Cook over low to medium for 10-15 minutes until the onion begins to brown and caramelize. Add in the garlic and jalapeno and cook for another minute. Reduce heat to low. Add the herb mix back to the pan. Stir in the tamarind paste, tomato paste, turmeric, curry, pepper and a pinch of salt.
Add 2 cups of water to this mixture, cover the pan with a lid and allow this mixture to simmer over low heat, stirring often so it doesn't burn, for 20-30 minutes. If it gets too dry, add a bit more water. You want a thick consistency at the end though.
In a wok or another skillet, heat 2 tbsp oil over high heat. Add the shrimp and cook, stirring occasionally until seared and just cooked through. Add to the stew and cook for another few minutes. Serve with hot rice.