Preheat the oven to 400F. Line a baking sheet with parchment paper.
Lay out butternut squashes pieces on the prepared baking sheet. Drizzle with olive oil, garlic powder, ground nutmeg, salt, and pepper. Toss to coat then roast in the oven until soft, about 40-50 minutes.
After the squash is done, heat butter in a large pot or dutch oven over medium heat. Once butter is melted, add the onions, garlic, italian seasoning, salt, and pepper. Toss to coat then saute until onions are soft, about 7-9 minutes.
Next, stir in the roasted butternut squash, canned tomatoes, and coconut milk then bring mixture to a simmer. Once simmering, reduce heat to low and cook for about 12-14 minutes, stirring occasionally.
Puree mixture using an immersion blender or transfer mixture to a high-speed blender then pulse until smooth. Divide between bowls, top with minced basil, and enjoy (preferably with a ooey gooey melty grilled cheese)!