Step 1: Prepare the butternut squash by peeling it carefully with a sharp vegetable peeler or knife. Cut it in half lengthwise and scoop out the seeds. Then, cut the squash into 1-inch cubes. Set aside.

Step 2: Heat the oil in a large, deep skillet or Dutch oven over medium heat. Add the chopped onion and sauté for 5-7 minutes until it becomes translucent and starts to golden.

Step 3: Add the minced garlic and grated ginger to the pan. Sauté for another 1-2 minutes until fragrant, being careful not to burn the garlic.

Step 4: Stir in the ground spices: cumin, coriander, turmeric, cinnamon, cardamom, and cayenne pepper. Toast the spices for about 30 seconds to 1 minute, stirring constantly to release their flavors and prevent burning.

Step 5: Add the diced tomatoes to the pan and cook for 2-3 minutes, stirring occasionally. This will help to deglaze the pan and create a flavorful base for the curry.

Step 6: Add the cubed butternut squash, drained chickpeas, coconut milk, and vegetable broth to the pan. Stir well to combine all ingredients and ensure the squash is mostly submerged in the liquid.

Step 7: Bring the mixture to a boil, then reduce the heat to low and simmer, partially covered, for about 20-25 minutes, or until the butternut squash is tender when pierced with a fork.

Step 8: Once the squash is cooked, use the back of a spoon to mash some of the squash pieces against the side of the pan. This will help thicken the curry and create a creamier texture.

Step 9: Taste and adjust the seasoning with salt and pepper. If you find the curry too acidic, add the optional brown sugar or maple syrup to balance the flavors.

Step 10: Stir in the fresh cilantro and lime juice. Let the curry simmer for an additional 5 minutes to meld the flavors.