Preheat the oven to 400°F. Peel the butternut squash, remove the seeds, and cut the flesh into 1 inch cubes. Core and dice the apples into 1/2 inch pieces. Chop the onion and mince the garlic. On a rimmed baking sheet, toss the squash and apples with 1 1/2 tablespoons of the olive oil and a generous pinch of salt and pepper. Spread everything into a single layer.

Roast on the top rack until the squash is fork-tender and the apples are browned around the edges, 25 to 30 minutes.

While the vegetables roast, heat the remaining 1/2 tablespoon olive oil in a large pot over medium heat. Add the onion and cook, stirring occasionally, until it softens and turns translucent, about 5 minutes. Add the garlic, cumin, and ginger and cook for 1 minute more, stirring constantly, until very fragrant.

Carefully add the roasted squash and apples to the pot along with any juices. Pour in the vegetable broth and stir to scrape up any browned bits from the bottom. Bring to a gentle simmer and cook for 10 to 15 minutes, letting the flavors meld.

Remove the pot from the heat. Puree the soup with an immersion blender until smooth and creamy, or transfer it in batches to a blender and blend on low until silky. Thin with extra broth or water if desired. Taste and adjust the seasoning with more salt and pepper.

Ladle the roasted butternut squash soup into warm bowls. Garnish each serving with chopped parsley and serve immediately with crusty bread.