Add onion, and cook until soft, about 3-5 minutes.
Add garlic, and cook, stirring frequently, for about 30 seconds.
Pour in chicken broth.
Add cauliflower, and cover skillet (I just use a piece of foil).
Let the cauliflower steam until fork-tender, about 10 minutes.
Carefully add cauliflower and broth mixture to a blender.
Add in fat-free half-and-half and dry mustard.
Blend until smooth.
Season with salt and pepper to taste.
Stir in shredded cheese, and let melt.
Garnish with a pinch of shredded cheddar or Parmesan cheese, if desired.
Notes
Broth: You can use vegetable broth if you would like to make the soup vegetarian.
Cauliflower: Feel free to use frozen steamable cauliflower in place of the fresh cauliflower florets. I just microwave the cauliflower in the steamer package according to the directions and then stir into the broth. There's no need to further steam the cauliflower, so just continue with the recipe as written.
Half-and-half: I use half-and-half to give it richness and creaminess without all of the fat of cream. I also used just enough cheese to give it some good flavor. I've received some negative feedback about the use of fat-free half-and-half in recipes because of some of the ingredients in it. Please always use your best judgment when making a recipe and feel free to use full-fat half-and-half, fat-free half-and-half or even cream depending on your dietary needs.
Cheese: The pepper jack adds a bit of flavor to the soup. If you prefer, use a different type of cheese, such as parmesan or asiago instead.
Blending: Be sure to blend the soup well if you like it really creamy.