Cauliflower Soup

http://food52.com/recipes/15247_paul_bertollis_cauliflower_soup

This recipe serves 8

3 tablespoons olive oil
1 medium onion (6 ounces), sliced thin
1 head very fresh cauliflower (about 1-1/2 pounds), broken into florets
Salt, to taste
5 1/2 cups water, divided
Extra virgin olive oil, to taste
Freshly ground black pepper, to taste

Warm the olive oil in a heavy-bottomed pan. Sweat the onion in the olive oil over low heat without letting it brown for 15 minutes.

Add the cauliflower, salt to taste, and 1/2 cup water. Raise the heat slightly, cover the pot tightly and stew the cauliflower for 15 to 18 minutes, or until tender. Then add another 4 1/2 cups hot water, bring to a low simmer and cook an additional 20 minutes uncovered.

Working in batches, purée the soup in a blender to a very smooth, creamy consistency. Let the soup stand for 20 minutes. In this time it will thicken slightly.

Thin the soup with 1/2 cup hot water. Reheat the soup. Serve hot, drizzled with a thin stream of extra-virgin olive oil and freshly ground black pepper.