For a heartier main-dish version, use 1 cup cauliflower and 1 cup peeled, diced potatoes instead of 2 cups cauliflower.
1. Place steamer basket and 1/2 inch of water in medium saucepan. Cover, and steam cauliflower 4 to 6 minutes, or until tender. Set aside.
2. Meanwhile, purée squash, broth, flour, and thyme in blender or food processor until smooth.
3. Bring squash purée to a boil in saucepan. Cover, reduce heat to medium-low, and simmer 10 minutes, whisking occasionally to prevent scorching.
4. Remove pan from heat, and stir in soy creamer. Add cauliflower and corn, and cook 1 to 2 minutes, or until heated through. Season with salt and pepper, if desired. Ladle soup into bowls, and top with green onions.