Extra-sharp Cheddar and malty English ale balance perfectly in this hearty soup.

2 medium leeks (white and pale green parts only), cut into 1/4-inch dice (2 cups)

2 medium carrots, cut into 1/4-inch dice (1 cup)

2 celery ribs, cut into 1/4-inch dice (1 cup)

2 teaspoons finely chopped garlic

1 Turkish or 1/2 California bay leaf

1/2 stick (1/4 cup) unsalted butter

1/3 cup all-purpose flour

2 cups whole milk

1 3/4 cups reduced-sodium chicken broth (14 fl oz)

1 (12-oz) bottle ale such as Bass

1 tablespoon Worcestershire sauce

1 teaspoon dry mustard

1 teaspoon salt

1/4 teaspoon black pepper

1 lb extra-sharp Cheddar (preferably English; rind removed if necessary), grated (4 cups)

4 bacon slices (3 1/2 oz total), cooked and crumbled

Preparation Wash leeks in a bowl of cold water, agitating water, then lift out leeks and drain in a colander. Cook leeks, carrots, celery, garlic, and bay leaf in butter in a 4-quart heavy saucepan over moderate heat, stirring occasionally, until vegetables begin to soften, about 5 minutes. Reduce heat to moderately low and sprinkle flour over vegetables, then cook, stirring occasionally, 3 minutes. Add milk, broth, and beer in a stream, whisking, then simmer, whisking occasionally, 5 minutes. Stir in Worcestershire sauce, mustard, salt, and pepper. Add cheese by handfuls, stirring constantly, and cook until cheese is melted, 3 to 4 minutes (do not boil). Discard bay leaf. Serve sprinkled with bacon.