Preheat your oven to 400 degrees Fahrenheit.
Using a sharp, sturdy knife, carefully cut off the stem of the butternut squash, then cut the squash in half vertically. Scoop out the seeds and either discard or save for roasting. Brush the inside of each half with 1 tablespoon olive oil and place cut side down on a rimmed baking sheet. Bake until a fork easily pierces the flesh, about 45 minutes. Remove squash halves from oven and set aside to cool a bit.
Set a medium pot over low heat. When hot, add the olive oil and then the onion. Sweat the onion, stirring occasionally, until tender and translucent but not golden, about 8 minutes.
Add 1 1/2 cups of the broth, ginger, 1/2 teaspoon salt, 1/4 teaspoon pepper, and maple syrup. Bring to a simmer. Simmer, covered, for 5 minutes.
Peel the skins off of the cooked butternut squash and add cooked flesh to the pot.
Using an immersion blender or working with a countertop blender in batches, puree the entire mixture.
Return the puree to the pan (if you are using a countertop blender; if you used an immersion blender, you’re already there!) Stir in the coconut milk. Bring back to a simmer. Taste and add additional salt and pepper if desired. If you prefer your soup to be thinner, add the remaining broth.
Remove from heat, ladle into bowls, and add garnishes if desired. Serve.
Store leftovers in an airtight container in the refrigerator. Keeps for about 3 days. Freeze in an airtight container for up to 3 months; to reheat, thaw overnight in the fridge and heat gently in a pan over the stove.
