Fennel and Potato Soup

Details

Ingredients

• 3 bulbs fennel - trimmed, quartered, and cored
• 1 tablespoon butter
• 1 tablespoon olive oil
• 3 spring onions, sliced
• 4 cups vegetable stock, divided
• 1 large potato, peeled and cubed
• ¼ cup water, or as needed
• ground black pepper to taste