Adapted from Sabrina Ghayour. Be sure to add a pinch of salt with each addition of veggies (and mushrooms), and then taste for more still. We liked this dish with a decent amount of salt.
Place the ingredients for the spice paste into a powerful blender or wet-dry grinder. Add enough water to just cover the ingredients and grind to a smooth paste. Set aside.
Heat the vegetable oil in a large and heavy sauce pan or Dutch oven over medium-high heat. Add the onions with a pinch of sea salt and cook, stirring, until the edges of the onions start to brown, about 8 minutes.
Add the mushrooms with another pinch of sea salt. Cook, stirring occasionally, until the mushrooms have released their water and are starting to brown.
Add the chicken with another pinch of sea salt. Stir it into the onions and mushrooms and then let it cook for 1 minute over medium heat. Stir the chicken and let it cook for another minute.
Stir the pistachio paste into the chicken. Add just enough cold water to barely cover everything and bring to a boil.
Cover and reduce the heat to maintain a gentle simmer and let cook for 10 minutes.
Add the butternut squash and corn with a pinch of sea salt, and return to a simmer. Cover and simmer gently for 20 minutes, or until the chicken is cooked through and the butternut squash is tender.
Add the juice of 2 limes and taste for more salt or lime juice.
Serve over Basmati rice and sprinkled with cilantro. Offer lime wedges on the side for those who like their curry with some extra punch.
*It has recently been brought to my attention that true Aleppo pepper is not currently available because of the situation in Syria. The Silk chile pepper that Burlap and Barrel sells is botanically identical, but for the most part I still see people selling "Aleppo" pepper. I tried asking at one retailer where it came from and got nowhere. So I am continuing to call for "Aleppo" pepper as a matter of ease for you (and also because I still have chile pepper labeled as Aleppo), but am no longer convinced what I am using is true Aleppo pepper. As long as it has a medium warmth and fruitiness, is not super hot, it will work just fine.