Warm the oil in a large pot or dutch oven over medium-high heat. Add the onion and apple and sauté until the onion is translucent, 3 to 5 minutes.
Add in the garlic, rosemary, sage, and a pinch of salt. Sauté for an additional 1 to 2 minutes, until fragrant.
Add in the squash, coconut milk, and vegetable broth. Stir well, then bring to a boil over high heat.
Reduce the heat to medium-low and simmer uncovered for 10 to 12 minutes, until the squash is fork-tender.
Carefully use an immersion blender to blend the soup until smooth. You can also transfer the soup to an upright blender with a venting lid; blend on high speed for 14 to 60 seconds, until creamy.
Serve as desired; leftovers will keep in the refrigerator for up to 5 days, or can be frozen for up to one month.
