How to Make It
In a large soup pot, melt the butter. Add the diced onion, crushed garlic cloves, thyme sprigs and bay leaf and cook over moderate heat, stirring occasionally, until the onion is softened, about 5 minutes. Add the cauliflower florets and chicken stock and bring to a simmer. Cover and cook over moderately low heat until the cauliflower is very tender when pierced with a fork, about 20 minutes. Discard the thyme sprigs and bay leaf.
In a blender or food processor, carefully puree the soup in batches until smooth. Pour the soup into a clean pot and set it over low heat. Stir in the heavy cream and season the cauliflower soup with salt and black pepper.
Meanwhile, in a medium skillet, cook the chopped chorizo over moderate heat until it is almost crisp, about 3 minutes. Add the panko and cook, stirring frequently, until the crumbs are crisp, about 5 minutes. Transfer the chorizo bread crumbs to a small bowl.
Ladle the soup into shallow bowls. Sprinkle with the chorizo bread crumbs and serve at once, before the bread crumbs get soggy.