The nutty gremolata makes a good flavor partner for cauliflower, and adds a bit of crunch to this luxurious soup.
1. In a large saucepan, heat the olive oil over medium heat. Add the onion and cook until soft, about 10 minutes. Add the cauliflower and sauté for 10 minutes, until it begins to brown. Add the garlic and coriander, and sauté for a minute. Add the chicken broth, and bring to a simmer. Cook until very soft, about 25 minutes.
2. Cool slightly, then purée in two batches in food processor or blender, a full minute per batch for a velvety soup. Strain through a mesh stainer into the pan. Add the cream. Simmer if a thicker soup is desired. Add the cayenne, lemon juice and salt and pepper to taste.
3. In a small skillet, heat the olive oil. Add the slivered almonds and panko, and sauté until golden. Remove from heat, and add parsley and lemon zest. Season to taste with salt and pepper.
4. Ladle the soup into bowls, and top with gremolata and a drizzle of olive oil just before serving.