creamy cauliflower soup

My son Blaine is a fan of America's Test Kitchen

and asked for a Cook's Illustrated Cookbook for Christmas.

So . . . I have been looking at their recipes and they always 

have a bit of culinary science woven in.

For example, their recipe for Cauliflower Soup has an interesting twist:
To really let the cauliflower shine, we cooked it in seasoned water 
rather than broth. We also added it to the saucepan in
two stages to ensure that our soup had both 
the grassy flavor of just-cooked cauliflower and 
the nuttier notes that come with longer cooking times.

Here is their recipe adapted a bit by me . . .

Creamy Cauliflower Soup

{America’s Test Kitchen}

Serves 4-6

"For a creamy cauliflower soup without cream, we relied on cauliflower’s low insoluble fiber content to produce a velvety smooth puree. To ensure that cauliflower flavor remained at the forefront, we cooked the cauliflower in seasoned water (instead of broth), skipped the spice rack entirely, and bolstered the soup with sautéed onion and leek. We added the cauliflower to the simmering water in two stages so that we got the grassy flavor of just-cooked cauliflower and the sweeter, nuttier flavor of long-cooked cauliflower. Finally, we fried florets in butter until both browned and used each as a separate, richly flavored garnish."

Ingredients

1 head cauliflower, (2 pounds)

8 tablespoons unsalted butter

1 leek, white and light green parts only, sliced, and washed thoroughly

1 small onion, halved and sliced thin

Salt and pepper

5 cups water

½ teaspoon sherry or white wine vinegar

Instructions

1. Pull off outer leaves of cauliflower and trim stem. Cut heaping 1 cup of 1/2-inch florets from head of cauliflower; set aside. 

2. Cut remaining cauliflower crosswise into 1/2-inch thick slices.

3. Melt 3 tablespoons butter in large saucepan over medium-low heat. Add leek, onion, and 1 1/2 teaspoons salt; cook, stirring frequently, until leek and onion are softened but not browned, about 7 minutes.

4. Increase heat to medium-high; add 4 1/2 cups water and half of sliced cauliflower. Bring to simmer. Reduce heat to medium-low and simmer gently for 15 minutes. Add remaining sliced cauliflower, return to simmer, and continue to cook until cauliflower is tender and crumbles easily, 15  minutes longer.

5. While soup simmers, melt remaining 5 tablespoons butter in 8-inch skillet over medium heat. Add reserved florets and cook, stirring frequently, until florets are golden brown and butter is browned and imparts nutty aroma, 6 to 8 minutes. Remove skillet from heat and use slotted spoon to transfer florets to small bowl. Toss florets with vinegar and season with salt to taste. Pour browned butter in skillet into small bowl and reserve for garnishing.

5. Process soup with an immersion blender about 45 seconds. Adjust consistency with remaining water ½ cup water as needed (soup should have thick, velvety texture but should be thin enough to settle with flat surface after being stirred) and seasoning with 1/2 tsp pepper and salt to taste.

6.  Serve, garnishing individual bowls with browned florets, drizzle of browned butter and seasoning with pepper to taste.

I am not sure I could separate the grassy flavor from the sweeter nuttier flavor but it was delicious.

{original recipe video}