If you have chosen to use fresh spices (like I recommend), heat a skillet over medium heat and add the coriander and cumin seeds. Toast until they start to become fragrant, about 3-5 minutes. Shake the pan periodically to ensure you don't burn them.
Remove the spices from the heat and grind in a spice grinder or with a mortar and pestle.
Heat a skillet over medium heat and add the ghee.
Add the onions and garlic and cook until softened, about 3-5 minutes.
Add the butternut squash and saute for 3-5 minutes.
Add the fresh spinach and cook, stirring periodically to prevent sticking and burning, until spinach is wilted. Add the ginger paste and cook for 1 minute.
Add the canned tomatoes, juice and all, and mix well. Scrape any stuck bits off the bottom of the pan. Simmer for 2 minutes.
Add the seasonings and cook for 1 minute. Add the broth and bring to a simmer. Cook for 3 minutes.
Add the coconut milk and bring to a simmer. Continue simmering for 5-7 minutes, until liquid has reduced and the the sauce is creamy. Stir in the fresh lime juice.
Remove from heat and garnish with chopped cilantro and fresh lime wedges. Serve with rice and/or naan.