1 1/2 Tbs olive oil
1 medium onion, coarsely sliced
1 small leek, white part only, coarsely sliced
1 stalk celery, coarsely sliced
1 carrot, peeled and coarsely sliced
1 large clove garlic, peeled and smashed
8 cups cold water
1 bay leaf

In a large saucepan, warm the oil over medium heat. Add the onion, leek, celery, carrot, and garlic, and cook, stirring occasionally, until the onion is translucent, about 15 minutes. Add the water and bay leaf, and bring to a boil. Reduce to a simmer and cook, partially covered, until the vegetables are very soft, about 1 hour. Strain the broth through a sieve into a clean bowl or heatproof container, pressing down on the vegetables to extract all their juices. Let cool, uncovered. Refrigerate in a sealed container for up to a week, or freeze for longer keeping.

Yield: About 6 cups, give or take a little