In winter, Berlin's vegetable offerings can be bleak, but cauliflower is one of the few things for sale at green markets and grocery stores that stands proud and tall, creamy white within its tightly furled green leaves. I like it steamed and served with a lemon vinaigrette or cloaked in a creamy mustard-dotted béchamel, roasted in the oven with capers and parsley or stewed on the stove-top with anchovies and mashed into a silky pasta sauce. But I'd never really thought of it for soup the way I do when I see a squash or a leek. Then a single spoonful of an ethereal cauliflower soup at a restaurant in Paris made it difficult for me to concentrate on anything else, so a few days after getting back from our holiday, I got to work.
Now, a word about appearances. Cauliflower soup will never win a beauty award. It will never enchant you with its looks. Unlike a glowing squash soup, for example, or a vivid spinach one, cauliflower soup is the quieter, younger cousin tending towards having bad posture. But that's kind of its appeal, too. It's quiet and unassuming, but deeply comforting and creamy (despite having nary of speck of dairy or animal fat in sight) and, actually, if dressed up in the right way - a sprinkling of Espelette pepper here, a pretty china plate there - it can be rather elegant.
Like all puréed vegetable soups, it barely requires a recipe. You stew a leek in olive oil until soft and translucent, though you could use an onion instead. You wash and slice your cauliflower roughly, tip the creamy florets into the pan for a little while, then add water and boil quietly until the cauliflower is soft and tender. What's important, I find, with cauliflower soup is that you must really lean on your immersion blender. You want the soup to be impossibly silky, free of the tiniest of lumps (unlike that little one lurking up there in the lower righthand corner). Purée until the soup takes on a gentle sheen and drips from the spoon like oil.
Turn to your seasonings, which are nothing more than salt and half a lemon squeezed into the soup. For color, you can sprinkle piment d'Espelette on each serving, but it's hardly necessary. I like a few homemade croutons, chewy peasant bread that you've roasted with a little slick of olive oil and a sprinkling of salt in the oven for a while, floating on top. The crunch and toast are a nice contrast to that sweet, vegetal purée.
Serves 4 to 5
1 leek or 1 onion
3 tablespoons olive oil
1 cauliflower, green leaves and trunk removed
Piment d'Espelette, optional
Homemade croutons, optional
1. Peel and clean the leek and cut into thin slices, discarding the tough green tops. Warm olive oil in a heavy pot and gently sauté the leek in the olive oil until wilted, 5 to 7 minutes. In the meantime, wash the cauliflower and slice thickly. Add the cauliflower to the pot and stir to combine. After 2 to 3 minutes, add enough water to cover the vegetables.
2. Bring the water to a boil, then lower the heat, cover the pot and simmer for 20 to 25 minutes. Remove from the heat and, using an immersion blender, purée until smooth and creamy. Add salt to taste and the juice of the 1/2 lemon.
3. Serve dusted with piment d'Espelette or homemade croutons.