Melt butter in a large pot and add onions, curry powder, and cinnamon. Cook, uncovered, over low heat for 10 minutes, until the onions are tender and fragrant – stirring occasionally.

Add the squash, apples, salt, pepper, and 2 cups of water to the pot. Bring to a boil, cover, and cook over low heat until the squash and apples are tender, about 20 minutes. Carefully transfer the mixture to a food processor or blender and puree until smooth. Alternatively, use an immersion blender.

Pour the soup back into the pot and stir in the broth and apple cider, adding more water if necessary to reach the desired consistency. Season to taste with salt and pepper and serve hot topped with croutons.

For the Croutons: Melt butter in large skillet over medium heat. Add bread cubes and toss to coat. Cook 8-10 minutes, tossing often, until bread is toasted. Serve on top of soup.