1 medium onion, finely chopped
2 celery ribs, strings removed with a vegetable peeler and ribs finely chopped
1/2 lb cauliflower, cut into 1-inch florets (2 1/4 cups)
3 tablespoons unsalted butter
2 cups chicken broth
1 cup plus 2 tablespoons whole milk
1 teaspoon cornstarch
1/3 cup crumbled Stilton cheese (2 oz)
1/2 cup light cream or half-and-half
1/4 teaspoon white pepper
1/8 teaspoon salt
Garnish: croutons and crumbled Stilton