Sauté the aromatics: In a large pot or Dutch oven, heat the olive oil or coconut oil over medium heat. Add the chopped onion and cook for 5-7 minutes, until softened and translucent. Add the minced garlic and grated ginger, cooking for another 1-2 minutes until fragrant.

1. Add the spices: Stir in the curry powder, cumin, turmeric, cinnamon, and cayenne pepper (if using). Cook for another minute to let the spices bloom and release their aroma.
2. Add the butternut squash: Add the cubed butternut squash to the pot, stirring to coat it with the spices.
3. Add liquids: Pour in the coconut milk, vegetable broth, and diced tomatoes. Stir everything together and bring the mixture to a simmer.
4. Simmer the curry: Cover the pot, reduce the heat to low, and let the curry simmer for 25-30 minutes, or until the butternut squash is tender.
5. Finish the curry: Stir in the spinach or kale (if using) and cook for another 3-5 minutes, until wilted. Taste the curry and adjust seasoning with salt and pepper if needed.
6. Serve: Serve the curry hot, garnished with fresh cilantro and lime wedges on the side.