1In a 4-quart saucepan, combine cauliflower, water and salt; bring to a boil.
2Reduce heat and let simmer until cauliflower is tender; let cool slightly.
3Transfer 2 cups cauliflower (including cooking liquid) to blender container and process until smooth.
4Repeat procedure, 2 cups at a time, until all cauliflower and cooking liquid have been processed; Set aside.
5In same saucepan heat butter over medium-high heat until bubbly and hot; add onion and saute until translucent.
6Sprinkle with flour and broth mix and stir quickly to combine; cook, stirring, for 1 minute.
7Gradually add milk and cook, stirring constantly, until flour mixture is completely dissolved and liquid thickens; stir in pureed cauliflower.
8Reduce heat and let simmer, stirring occasionally, until heated through; stir in pepper.
9Ladle into 4 soup bowls and, if desired, sprinkle each portion with dash nutmeg.