- 1 large head cauliflower (about 2 pounds), cut into bite-size florets
- 3 tablespoons extra-virgin olive oil, divided
- Fine sea salt
- 1 medium red onion, chopped
- 2 cloves garlic, pressed or minced
- 4 cups (32 ounces) vegetable broth
- 2 tablespoons unsalted butter
- 1 tablespoon fresh lemon juice, or more if needed
- Scant ¼ teaspoon ground nutmeg
- 2 tablespoons finely chopped fresh flat-leaf parsley, chives and/or green onions
- Preheat the oven to 425 degrees Fahrenheit. If desired, line a large, rimmed baking sheet with parchment paper for easy cleanup.
- On the baking sheet, toss the cauliflower with 2 tablespoons of the olive oil until lightly and evenly coated in oil. Arrange the cauliflower in a single layer and sprinkle lightly with salt. Bake until the cauliflower is tender and caramelized on the edges, 25 to 35 minutes, tossing halfway.
- Once the cauliflower is almost done, in a Dutch oven or soup pot, warm the remaining 1 tablespoon olive oil over medium heat until shimmering. Add the onion and ¼ teaspoon salt. Cook, stirring occasionally, until the onion is softened and turning translucent, 5 to 7 minutes.
- Add the garlic and cook, stirring constantly, until fragrant, about 30 seconds, then add the broth.
- Reserve 4 of the prettiest roasted cauliflower florets for garnish. Then transfer the remaining cauliflower to the pot. Increase the heat to medium-high and bring the mixture to a simmer, then reduce the heat as necessary to maintain a gentle simmer. Cook, stirring occasionally, for 20 minutes, to give the flavors time to meld.
- Once the soup is done cooking, remove the pot from the heat and let it cool for a few minutes. Then, carefully transfer the hot soup to a blender, working in batches if necessary. (Do not fill past the maximum fill line or the soup could overflow!)
- Add the butter and blend until smooth. Add the lemon juice and nutmeg and blend again. Add additional salt, to taste (I usually add another ¼ to ¾ teaspoon, depending on the broth). This soup tastes amazing once it’s properly salted! You can also a little more lemon juice, if it needs more zing. Blend again.
- Top individual bowls of soup with 1 roasted cauliflower floret and a sprinkle of chopped parsley, green onion and/or chives. This soup keeps well in the refrigerator, covered, for about four days, or for several months in the freezer.