Preheat oven to 400 ˚F. Line baking dish with parchment paper. Place peeled and cubed squash, sliced apples, chopped onion, and sliced garlic on paper. Sprinkle ginger overall and mix gently. Roast in oven until tender and slightly brown about 40 minutes.
Remove from oven and place mixture in a saucepan. Add 2 cups broth and puree with a potato masher or hand blender. Add remaining stock and simmer over medium heat until bubbly.
Top with dollop of light sour cream and chopped parsley.