1 - Add the butter to a large Dutch oven or other heavy-duty pot over medium heat.

2 - When the butter has melted, add the onion and sauté until translucent.

3 - Add the cabbage, carrot, and celery.

4 - Sauté until the vegetables begin to soften, stirring frequently, about 3 minutes.

5 - Add the bay leaf and vegetable stock and bring to a boil over high heat.