What I love about vegetable soups like this one is that they boast the soul satisfying consistency of cream without actually containing any. Cooked and pureed, most vegetables are amazingly creamy all by themselves. (OK, some of them need to be pureed with potato to create the desired effect, but you get my point.) I love cream, but it is heavy and although it delivers nice mouth feel, it dulls the flavor of whatever you are eating. When you put a spoonful of cauliflower soup into your mouth the first thing you want to taste is cauliflower.
The rye croutons called for here pick up the caraway in the soup, but if you don’t want to go the extra few yards and make your own, just use good-quality store-bought croutons. The point is to have a contrast in texture: creamy soup/crunchy croutons.
This recipe will freeze beautifully, so make a double batch and keep half of it for a cold or rainy day.
Three 1/2-inch thick slices rye bread
2 tablespoons olive oil
Kosher salt and freshly ground black pepper to taste
1 medium head cauliflower
1 medium Yukon Gold potato, peeled
4 tablespoons (1/2 stick) unsalted butter
1 large onion, thinly sliced
2 teaspoons caraway seeds
1 quart chicken stock, preferably homemade plus more as needed for thinning
2 teaspoons fresh lemon juice
2 plum tomatoes, seeded and chopped
2 tablespoons snipped fresh chives
Preheat the oven to 350ºF. Remove the crust from the bread and cut the bread into 1/2-inch cubes. Place in a large bowl and toss with the olive oil. Arrange in one flat layer on a baking sheet and bake in the middle of the oven, stirring often, until lightly browned, about 20 minutes. Season with salt and pepper.
Remove 1 cup florets from the cauliflower and trim into 1/2-inch pieces. Bring a saucepan of salted water to a boil over high heat. Add the florets and bring back to a boil. Boil rapidly until tender, about 3 minutes. Drain and rinse under cold running water. Set aside to drain on paper towels until just before serving the soup.
Slice the remaining cauliflower and the potato. Heat 3 tablespoons of the butter in a soup pot or kettle over medium heat. Add the onion and caraway seeds and cook, stirring, until the onion has softened, about 5 minutes. Stir in the sliced cauliflower and potato. Pour in just enough of the chicken stock to barely cover the cauliflower. Season with salt and pepper and increase the heat to high. Bring to a boil, reduce the heat to medium, and simmer until the cauliflower is tender, about 20 minutes. Working in batches, puree the soup in a food processor or blender until smooth. (Or puree the soup right in the pot using an immersion blender.) Return the soup to the pot and reheat over low heat. Stir in the lemon juice and season with salt and pepper. Thin to the desired consistency with stock or water if necessary. You should have about 5 cups.
Heat the remaining tablespoon of butter in a small skillet over medium heat. Add the tomatoes, reduce the heat to low, and cook, stirring often, until thick and pulpy, about 5 minutes. Season with salt and pepper.
Add the cauliflower florets to the soup and cook over medium heat just until warmed through. Serve the soup in warmed bowls. Garish with the croutons, a spoonful of the tomatoes, and the chives.