Butternut Squash-Sweet Potato Ginger Bisque recipe.

Ingredients
1 (2 pound) butternut squash - peeled, seeded, and cut into large chunks
4 sweet potatoes, peeled and cut into chunks
1 onion, peeled and chopped
1 (2 inch) piece fresh ginger, peeled and finely chopped
3 cloves garlic, peeled and chopped
1 1/2 quarts water, or amount to cover
1 cup plain yogurt, or amount desired (optional)
salt and ground black pepper to taste

Directions
Place the squash, sweet potatoes, onion, ginger, and garlic in a large pot. Pour in enough water to cover the vegetables. Bring to simmer over medium heat, and cook until vegetables are tender and can be easily pierced with a fork, 30 to 45 minutes.
Remove pot from heat. Place soup in batches into a blender or the bowl of a food process. Pulse until smooth. Return soup to pot, and whisk in yogurt. Season with salt and pepper to taste. If necessary, reheat soup over low heat, but do not allow to boil.