Pull off outer leaves of cauliflower and trim stem. Using paring knife, cut around core to remove; thinly slice core and reserve for step 2. Cut remaining cauliflower crosswise into ½-inch thick slices.
Peel and slice onion. Place onion in the bottom of the Instant Pot liner. Add salt, garlic powder and a few turns of freshly ground pepper. Add the thinly sliced cauliflower core. Top with cauliflower slices. Place liner in the Instant Pot.
Pour in the chicken stock (bone broth) over the cauliflower slices. Place liner in your instant pot.
Lock the lid in place, set to sealing. Hit [Manual] reduce time to 1 minute. When the pot beeps immediately do a QPR (quick pressure release).
Remove a piece of sliced cauliflower and set aside. Either ladle the cauliflower with some broth into a Vitamix 64 ounce container or use a stick blender and puree right in the liner. I like to use my Cuisinart Stick Blender because it makes for less clean up. Blend until very smooth. If using the Light Laughing Cow Cheese add to your soup along with the nutritional yeast and blend until smooth.
Once your soup puree is smooth chop your reserved cauliflower slice into small, spoon size pieces and add back into your soup. Taste and season with additional salt or pepper if needed.
To serve garnish with chopped chives or parley and turkey bacon crumbles.