In a large glass mixing bowl, soak a tamarind slab (break into pieces first) in 5-6 cups of hot water (I boil the water in a kettle and pour over the tamarind pieces). Let the tamarind soak and release its flavor into the water for about 1 hour. Then squeeze the pulp with clean hands until you remove as much pulp as possible from the tamarind pieces. Then strain this tamarind water into a separate saucepan, bring to a boil and simmer tamarind water on low heat for at least 30-35 minutes, until reduced. Set reduced tamarind water aside.
Rinse and pat dry the eggplants. Carefully, place 4 slits lengthwise in the eggplants and sprinkle with Kosher salt. This allows for some water to be drawn out, along with some bitterness of the eggplants. Leave for 30 minutes or so.
Heat a saute pan on medium heat. Dry roast the peanuts, shredded coconut and sesame seeds (each separately in batches). Be careful so as not to burn any of these ingredients. Carefully stir as needed with a heat-resistant spatula until a fragrant aroma is released and the color changes to a light brown. This takes no more than 2-3 minutes, per batch. Set aside until cool. Then place these roasted ingredients into a blender and blend/pulse really well. Once you achieve a fairly smooth paste, add the fried onions and peanut butter and pulse again for several minutes. I add approximately 1-2 cups of water, as needed, while blending (a little bit at a time) to ensure a very smooth paste. Set this ground mixture aside.
Heat a wok or frying vessel on medium high heat. Add enough Canola oil for deep frying. Once the oil is hot, slowly add the eggplants and fry on medium high heat for 2-3 minutes. Then turn heat to medium low and continue to fry for an additional 8-10 minutes, turning as needed. The goal is to ensure the eggplants are almost cooked on the inside and become fairly soft. Remove and place the eggplants on a paper-towel lined baking sheet to absorb any excess oil. If using the Anaheim peppers as well, fry these separately (about 7-8 minutes until peppers are soft) once the eggplants are done (you also want to slit and deseed the peppers beforehand). Set aside.
Heat a Dutch oven, or heavy-bottomed cooking vessel on medium heat and add 3 tbsp of Canola oil. Once oil is heated, add the mustard seeds (smallest size), cumin seeds and fenugreek seeds and saute for 4-5 minutes, stirring as needed. Add about 6-8 curry leaves and stir. Saute for 2-3 minutes. Now add the ginger and garlic pastes, mix well and continue to saute for 5 minutes. Turn heat to medium low and now add the spices. First add the coriander powder, mix well and saute for 2-3 minutes. Add 1 tsp of water as needed to prevent burning of spices and mix well. Now add the cumin powder, mix again and saute for 2 minutes. Now add remaining spices (Kashmiri Lal Mirch, turmeric powder, and salt) and continue to saute for 5-7 minutes on medium low heat, adding a few teaspoons of water as needed.
Once the oils are released in this spice mixture and it becomes aromatic (total cooking time of about 25 minutes on medium low to low heat), add the blended/ground mixture of fried onions, roasted coconut, sesame seeds, peanuts and peanut butter. Mix everything really well and cook on medium heat for 5-8 minutes until it reaches a boil. Now turn heat to medium low, cover and continue to cook for 40-45 minutes (stirring a few times in between as needed).
Uncover the Dutch oven, and now add the tamarind water and mix well. Turn heat to medium high until it reaches a boil. Once the gravy reaches a boil, turn heat back to medium low and continue to cook for an additional 25-30 minutes. Then uncover, add the fried eggplants/Anaheim peppers and carefully mix. Add an additional 6-8 curry leaves on top, cover and simmer on low heat for about 10 minutes.
Baghaar-e-Baingaan is now ready. Serve with Biryani, or plain Basmati rice, or even homemade parathas! Once you take that first bite, you will no doubt realize that every step involved was worth it! Nosh Farma'aiye. Enjoy!