This creamy soup has a delicate anis taste and it's delicious with or without its garnish.

In a large saucepan over medium heat, heat the oil and butter and cook the onions 5 minutes without browning them, stirring occasionally.
Add the fennel, potato, broth, salt and pepper and bring to a boil. Reduce the heat, cover and simmer for about 30 minutes until the vegetables are very tender.
Puree the soup using a hand blender or blender.
If desired, place a small amount of garnish on each bowl of soup just before serving.
Toss the tomatoes, olives and herbs with oil and spoon a tablespoon over each bowl just before serving.