In a large skillet over medium heat, heat oil until it shimmers.
Add in onion along with a pinch of salt to draw out moisture. Sauté for 5-8 minutes, until you begin to see some light caramelization.
Add in garlic, ginger, and green peppers and continue to sauté for another 1-2 minutes, until very fragrant.
Add in all the spices (cumin, coriander, chili powder, turmeric, and cinnamon) and stir to coat. If the mixture is sticking quite a bit to the pan, add a splash of water and gently scrape with your wooden spoon to get it to release. Cook this mixture for another 1-2 minutes, stirring often, to remove the raw flavor of the spices.
Add in the rinsed chickpeas and the coconut milk and stir to combine everything. (If you did not roast the butternut squash, add it in now. If you roasted it, we will add it at a later point.)
Bring the mixture up to a boil and then reduce heat to low or medium-low to establish a simmer. Simmer for 12-15 minutes, stirring occasionally. (If you added in the uncooked squash in the last step, simmer until the squash is tender.)
Add in the roasted squash and the spinach. Simmer for about 5 minutes, until squash is heated through and spinach is wilted.
Give it a taste and adjust salt to preference.
I love to serve this with steamed basmati rice. Garnish with a squeeze of fresh lime juice and fresh cilantro. A handful of chopped peanuts is a nice touch as well.