Preparation Wash leek slices in a bowl of cold water, agitating, then lift out and pat dry. Melt butter with water in a 4- to 5-quart heavy saucepan over moderate heat. Add cauliflower and leek and cook, uncovered, stirring occasionally, until cauliflower begins to soften (do not let brown), about 5 minutes. Add coriander and cook, stirring, 1 minute, then add broth, milk, salt, and pepper and bring to a simmer, stirring occasionally. Reduce heat and gently simmer, covered, stirring occasionally, until cauliflower is very tender, 15 to 20 minutes. While soup is cooking, toast almonds in a dry skillet over moderately low heat, stirring frequently, until fragrant and a shade darker, about 3 minutes. Purée soup in 2 batches in a blender (use caution when blending hot liquids) until very smooth. Serve soup topped with almonds. Cooks' note:Soup can be made 2 days ahead and chilled, covered. Almonds can be toasted 2 days ahead and kept separately in an airtight container at room temperature. Reheat soup before serving.
Preparation Wash leek slices in a bowl of cold water, agitating, then lift out and pat dry. Melt butter with water in a 4- to 5-quart heavy saucepan over moderate heat. Add cauliflower and leek and cook, uncovered, stirring occasionally, until cauliflower begins to soften (do not let brown), about 5 minutes. Add coriander and cook, stirring, 1 minute, then add broth, milk, salt, and pepper and bring to a simmer, stirring occasionally. Reduce heat and gently simmer, covered, stirring occasionally, until cauliflower is very tender, 15 to 20 minutes. While soup is cooking, toast almonds in a dry skillet over moderately low heat, stirring frequently, until fragrant and a shade darker, about 3 minutes. Purée soup in 2 batches in a blender (use caution when blending hot liquids) until very smooth. Serve soup topped with almonds. Cooks' note:Soup can be made 2 days ahead and chilled, covered. Almonds can be toasted 2 days ahead and kept separately in an airtight container at room temperature. Reheat soup before serving.