yellow onion, sliced
head cauliflower, chopped
low-sodium chicken broth
small crusty rolls
(8 ounces) grated white Cheddar
kosher salt and pepper
- Heat 1 tablespoon of the oil in a saucepan over medium-high heat. Add the onion and cook, stirring, until soft, about 5 minutes.
- Add the cauliflower, broth, and milk and simmer until tender, about 15 minutes.
- Cut the rolls in half. Layer the bottoms with the prosciutto and watercress. Drizzle with 1 tablespoon of the oil. Top with the roll halves.
- Puree the soup in the pan using a handheld immersion blender or, working in batches, a standard blender.
- Stir in 1 ⅔ cups of the Cheddar, 1 teaspoon salt, and ¼ teaspoon pepper.
- Divide the soup into bowls. Add the remaining oil and Cheddar and ¼ teaspoon pepper. Serve with the sandwiches.