Cut up the cauliflower, stems included, into small pieces and place in a large colander. Rinse thoroughly under running water and let drain briefly when finished.
Place cauliflower in the Instant Pot with garlic, the white part of the green onions, and the dried parsley. Add 2-3 tablespoons of water and season with salt and pepper, to taste.
Close your Instant Pot and cook on low pressure for 5 minutes. Allow it to release pressure naturally for 5 minutes, then release the remaining pressure.
Add the chicken stock to the Instant Pot and blend until smooth using and immersion blender. You may also use a blender, but make sure the blender lid is adequately vented to allow steam to escape before turning on the blender.
Turn the Instant Pot on saute, then add the goat cheese and stir until well blended. Cook another minute or two, or until the soup is uniformly heated. If the soup is too thick, add additional stock to reach the desired consistency. If it is too thin, continue cooking until excess moisture has been reduced.
Taste and season with additional salt and pepper, if desired. Serve immediately topped with sliced green onion or crumbled bacon.