Pumpkin Soup with Gruyere

Bahan-bahan (6 porsi)

• ¼ cup (½ stick) unsalted butter
• 1 large onion, (finely chopped)
• 4 cups vegetable broth
• 4 cups canned unsweetened pumpkin puree
• 1 whole bay leaf
• 1 cup half and half cream
• 1 tablespoon grated orange zest
• 1 tablespoon freshly squeezed orange juice
• 1 tablespoon freshly squeezed lemon juice
• ¾ teaspoon ground nutmeg
• ¾ teaspoon ground ginger
• 1½ cups shredded Gruyere or Swiss cheese, (divided)
• salt and ground white pepper
• 2 tablespoons finely chopped fresh chives
• croutons ((see Notes below))