- 2 tablespoons olive oil
- 3 large leeks, cleaned and thinly sliced
- 4 large stalks celery, thinly sliced
- 3 large white onions, peeled and halved
- 1 large fennel bulb, thinly sliced
- 2 large baking potatoes, peeled and cut into 1/2-inch cubes
- 1 tablespoon salt
- 1 1/2 teaspoons ground black pepper
- 8 cups water
- 2 cubes vegetable bouillon
In a large saucepan or soup kettle over medium-low heat, place the olive oil, leeks, celery, onions, fennel, potatoes, salt, and pepper, and cook and stir until the onions are translucent and the vegetables have begun to soften, about 10 minutes.
Pour 8 cups of water over the vegetables, bring to a boil, reduce the heat, and drop in the vegetable bouillon cubes. Simmer over low heat, stirring occasionally to dissolve the cubes, until the vegetables are tender and the potatoes have begun to thicken the soup, about 30 minutes.