Preheat large pot on medium heat and add butter to melt. Add onion and cook for 3 minutes, stirring occasionally. Add cauliflower and carrots, cook for 3 more minutes, stirring occasionally.
Add vegetable broth and milk, then stir, cover and bring to a boil. Reduce heat to low and cook soup for 10-12 minutes or until vegetables are fork tender.
Remove soup from heat and add hot sauce and garlic powder. Using an immersion blender, puree soup until smooth.
Add chickpeas or corn and stir. Serve soup hot garnished with blue cheese crumbles and green onion.
Notes
Store: Refrigerate in an airtight container for up to 3 days.