In a large saucepan, melt the butter over medium heat. Add the onion and sauté until it begins to turn golden, 4 to 5 minutes. Add the broth, pumpkin puree, and bay leaf. Bring to a boil, reduce the heat to low, cover, and simmer 15 to 20 minutes. Discard the bay leaf.
In small batches, purée the soup in a food processor or a blender. Return the purée to the pan and stir in the half and half, orange zest, orange and lemon juices, nutmeg and ginger.
Stir in 1 cup of the shredded cheese. Heat over low heat until the cheese melts and blends in. Season to taste with salt and white pepper. Pour into individual bowls and garnish with remaining cheese, chives and croutons (if desired).
Notes
To make homemade croutons: Preheat the oven to 350 degrees F. In a medium bowl, toss 2 cups of bread chunks with 2 tablespoons salted butter 1/2 teaspoon garlic powder and 1/4 teaspoon Italian seasoning. Spread onto a rimmed baking sheet. Sprinkle with 2 tablespoons finely grated Parmesan. Bake for 15 minutes. Let cool at room temperature.
Nutritional information does not include croutons.
If preparing the recipe as GLUTEN-FREE, omit the croutons and make sure the vegetable broth you're using is known to be GF.