Serves 4

3 tablespoons unsalted butter
1 medium onion, finely chopped
2 celery ribs, strings removed, finely chopped
2 medium garlic cloves, minced
1 small head cauliflower, (about 2 pounds) cut into 1-inch florets
3 cups chicken broth
1/2 cup milk
2 teaspoons cornstarch
1/3 cup crumbled Stilton cheese
1/2 cup light cream or half-and-half
1/4 teaspoon white pepper
1/8 teaspoon salt
Garnish:
croutons and crumbled Stilton

Combine butter, onion, celery, garlic and cauliflower in a 3 1/2- to 4-quart heavy saucepan over moderate heat, stirring occasionally, until onion and celery are softened, 8 to 10 minutes. Add broth and simmer, covered, until cauliflower is very tender, about 25 minutes.
Purée cauliflower mixture in 2 batches in a blender until very smooth, then return to cleaned saucepan and bring to a simmer.
Whisk together cornstarch and milk in a small bowl until cornstarch is dissolved, then add to soup and simmer, whisking, until soup is slightly thickened, 1 to 2 minutes.
Add Stilton, cream, pepper, and salt and cook over low heat, whisking, until Stilton is melted and soup is smooth, about 1 minute Garnish with croutons and crumbled Stilton.