Place the small cauliflower florets in a pot of water, and boil over medium high heat for 5-6 minutes until they are just starting to soften. Rinse well with cold water and drain completely.
In a mixing bowl, combine the egg yolks, sour cream, mayo, apple cider vinegar, mustard, celery seed, garlic powder, paprika and salt or pepper to taste. Whisk until the yolks are broken up and the mixture is combined.
Place the cauliflower into a large bowl, and add the celery, chopped egg, dill and green onions.
Pour the sauce mixture over the top of the cauliflower mixture in the bowl, and toss well to combine. Serve immediately or refrigerate to chill before serving.