Prepare the cauliflower by cutting the head into bite sized florets and steaming in a silicone steamer (as shown) for 3-4 minutes or in a stovetop steamer until the cauliflower is only slightly tender.

Set aside to cool. Make the dressing by whisking together sour cream, mayo, vinegar, mustard, celery seed, and salt. Mash the two reserved yolks into the cream mixture and whisk until very smooth. Add the cooled cauliflower, boiled eggs, celery, onion and dill.

Stir to coat. Refrigerate for about 1 hour to allow the cauliflower to completely cool and the flavors to melt together.

Garnish with green onion and serve cold!