Step 1

Heat a medium Dutch oven or stockpot over medium-high heat for 2 minutes. Add the butter, onion, leek, garlic, carrot, and celery and cook, stirring often, until the vegetables have softened and are lightly browned, about 6 minutes. Add the beer, cheese, Worcestershire, thyme, salt, and 1 teaspoon pepper and stir well. Bring to a boil, stirring often, then turn the heat to medium and simmer uncovered, stirring often, for 45 minutes to blend the flavors. Add the bread and continue cooking, stirring often, until the bread softens, about 15 minutes.

Step 2

Remove the pan from the heat and let cool slightly. Working in batches, transfer to a blender and process on medium speed until completely smooth, about 2 minutes.

Step 3

Return the soup to the pot and reheat gently until hot. Ladle into individual bowls, sprinkle with the chives and a dusting of pepper, if desired, and serve immediately.