Instructions
Step 1
In a medium bowl, soak the tamarind pulp in ¼ cup of warm water until soft, 10–15 minutes. Add enough additional water to measure 2½ cups, then discard the pulp and any seeds. If using tamarind paste, stir it together with 2½ cups of water in a medium bowl.
Step 2
Stir in the coconut milk, season to taste with salt, and set aside.
Step 3
To a medium pot over medium-high heat, add the oil. When it’s hot and shimmering, add the fish curry masala, coriander, black mustard, cumin, fennel, and fenugreek, and cook until fragrant, 1–2 minutes. Add the curry leaves and cook until they sputter, about 30 seconds. Add the green chiles (if desired) and onions and cook, stirring occasionally, until the onions are soft and translucent, 5–7 minutes. Add the ginger-garlic paste and continue cooking, stirring occasionally, until fragrant and lightly golden, 2–3 minutes more.
Step 4
Add the reserved tamarind water and bring to a boil, then turn the heat to medium and cook until slightly thickened, 5–7 minutes.
Step 5
Add the eggplant and okra, and bring back to a boil, then turn the heat to medium-high and cook until the eggplants are soft but retain some bite, 7–10 minutes. Add the tomatoes and cook until slightly tender, 5–8 minutes. Add the fish and continue cooking until just firm, 5–7 minutes more. Remove from the heat.
Step 6
Garnish with the cilantro and serve with the rice, dosas, or naan.