1. Heat oil in a large saucepan. Add green onion, green garlic (or garlic) and 1/4 teaspoon salt. Saute 10 minutes or until tender. Add cauliflower, sweet potato and white potato. stur well. Add chicken stock and water. Cover and simmer 30 minutes or until vegetables are tender. Mash vegetables. Add milk and stir well. For a creamy soup, use an immersion blender. Add cheese, cook over low heat 10 minutes.