Preheat the oven to 400°F (205°C) and line a rimmed baking sheet with parchment paper.
Cut the butternut squash in half and scoop out the seeds (reserve the seeds for later). Place the squash on the pan and drizzle each half with just enough olive oil to lightly coat the squash on the inside (about 1 tsp./5 ml each). Rub the oil over the inside of the squash and sprinkle it with salt. Turn the squash cut side down and roast until it is tender and completely cooked through, about 45-50 minutes. Set the squash aside until it’s cool enough to handle, about 10 minutes. Then use a large spoon to scoop the butternut squash flesh into a bowl and discard the tough skin.
Meanwhile, in a large pot, heat up the olive oil over medium heat. Add the onion and garlic, lower the heat to medium, and cook, stirring, until soft and lightly golden, about 10 minutes; lower heat as necessary to prevent burning.
Add all the ingredients (squash, onions with coconut milk, broth, ginger, maple syrup, lime juice) into a blender and blend until smooth and creamy. Season with salt. Return the soup to the pot and thin, if necessary, with additional stock until desired consistency is reached. If you're working with an immersion blender, add all the ingredients to the pot, bring the mixture to a simmer and cook, stirring occasionally, for 15 minutes so the flavors have a chance to meld. Carefully use your immersion blender to blend the soup completely.
Store leftover soup well covered in the refrigerator for 3-4 days.
For longer term storage, freeze in an airtight container for up to 3 months. The easiest way to reheat frozen soup is to remove it from the freezer and place it in the refrigerator 24 hours before reheating to thaw slightly. Reheat on a stovetop, adding extra 1/4 cup (60 ml) water/broth at a time if too thick.
Preheat oven to 300°F (150°C).
Pinch away all the large chunks of squash flesh and strings and put the seeds into a strainer. Place the strainer under cool running water and remove any additional squash flesh.
Put the seeds on a baking tray. Drizzle them with a small amount of oil, and sprinkle with a pinch or two of salt. Toss the seeds until they are evenly coated with oil and salt. Spread them out into a single layer,
Toast until the seeds are just starting to brown, about 20-25 minutes. Remove the seeds from the oven and let them cool on the tray.