Preheat oven to 425°F.
Cut the florets off of the thicker center stalk of the cauliflower.
Chop the florets into bite sized pieces and transfer to a parchment paper lined baking sheet.
Using your hands, toss the cauliflower with olive oil, salt and pepper.
Bake 15-20 minutes or until tender crisp.
Set aside to cool completely.
In a small bowl, whisk the mayonnaise, sour cream, sweet relish, Dijon, apple cider vinegar, salt, and pepper.
In a large mixing bowl, combine the cooled cauliflower, radishes, celery, cheese, green onions and bacon.
Pour the dressing over the cauliflower mixture and toss to combine. Allow to chill for 2 hours before serving.