If you can’t remember the last time you ate cauliflower soup, we understand. Many versions are characterless and bland. They smother cauliflower’s delicate flavors in cream or an overload of spices. What’s memorable about that?
But Editor in Chief Dan Souza knew that treated right, cauliflower contains a range of complex flavors, from grassy and vegetal to nutty and even sweet.
He was able to coax out the full spectrum of these flavors to create an elegant and unforgettable cauliflower soup. That’s not all: This soup recipe manages to be lush and creamy without a speck of cream.
How did Dan do it? He undercooked some of the cauliflower and overcooked the rest.
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How to Coax Out Cauliflower’s Full Range of Flavors
Cauliflower, like all cruciferous vegetables, contains odorless compounds that convert into aromatic ones; some convert when you cut it and some when you cook it. One such compound is dimethyl disulfide, which becomes a pungent gas at cooking temperatures and is responsible for cauliflower’s grassy, faintly sulfurous flavors.
For the first 15 minutes of cooking, the concentration of dimethyl disulfide is relatively high. Over time it dissipates, allowing the sweeter, nuttier flavors of other compounds, such as diacetyl and octanone, to come forward.
Armed with this knowledge, Dan cooked some of the cauliflower for 30 minutes and the other half for just 15 minutes. Simmering the vegetable in two stages gave his recipe both the grassy flavor of just-cooked cauliflower and the sweeter, nuttier flavor of the long-cooked vegetable.
And the texture? A gorgeously smooth, creamy puree.
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The Science Behind Why Cauliflower Is Creamy
How much a vegetable breaks down when it is cooked and pureed depends largely on one thing: fiber. Vegetables have two kinds—soluble and insoluble.
When subjected to heat and liquid, soluble fiber breaks down and dissolves, providing viscosity, while insoluble fiber remains stable even when pureed. Cream’s lubricating effect goes a long way toward mitigating the graininess of insoluble fiber, which is why cream is so often included in pureed vegetable soups.
Cauliflower, however, is fairly low in overall fiber—and especially in insoluble fiber. This is why cauliflower can be blended to an ultrasmooth, creamy consistency—with no cream added.
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More Ways to Keep Cauliflower at the Forefront
Dan had a few other tricks that allowed him to lean into the cauliflower’s flavors:
- Cooking the cauliflower in plain water. Chicken and vegetable broth muddied the flavors, while water kept it clean tasting.
- Skipping the spice rack. Spices can too easily overwhelm cauliflower, so the only seasonings are salt and pepper.
- Bolstering flavors with onion and leek. The sweetness from the onion and the earthiness from the leek complemented the more vegetal cauliflower notes.
- Adding a drizzle of browned butter and a tangy fried-cauliflower garnish. Frying florets in butter browned both the vegetables and the butter itself, creating two rich garnishes to contrast with the clean-tasting puree. Sherry vinegar tossed with the fried florets gave them savory tang.
This soup tastes intrinsically of cauliflower, and it is at once grassy, pleasantly sulfurous, sweet, and nutty. It uses one pan, one blender, five ingredients (besides water and salt and pepper), and couldn’t be easier.
Try it for yourself!
Creamy Cauliflower Soup
Serves 4 to 6
- 1 head cauliflower (2 pounds)
- 8 tablespoons unsalted butter, cut into 8 pieces
- 1 leek, white and light green parts only, halved lengthwise, sliced thin, and washed thoroughly
- 1 small onion, halved and sliced thin
- Salt and pepper
- 4½–5 cups water
- ½ teaspoon sherry vinegar
- 3 tablespoons minced fresh chives
Before You Begin: White wine vinegar may be substituted for the sherry vinegar. Be sure to thoroughly trim the cauliflower's core of green leaves and leaf stems, which can be fibrous and contribute to a grainy texture in the soup.
1. Pull off outer leaves of cauliflower and trim stem. Using paring knife, cut around core to remove; thinly slice core and reserve. Cut heaping 1 cup of ½-inch florets from head of cauliflower; set aside. Cut remaining cauliflower crosswise into ½-inch-thick slices.
2. Melt 3 tablespoons butter in large saucepan over medium-low heat. Add leek, onion, and 1½ teaspoons salt; cook, stirring frequently, until leek and onion are softened but not browned, about 7 minutes.
3. Increase heat to medium-high; add 4½ cups water, sliced core, and half of sliced cauliflower; and 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 to 20 minutes longer.
4. 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 in blender until smooth, about 45 seconds. Rinse out pan. Return pureed soup to pan and return to simmer over medium heat, adjusting consistency with remaining 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 salt to taste. Serve, garnishing individual bowls with browned florets, drizzle of browned butter, and chives and seasoning with pepper to taste.