Preheat oven to 400°F.
Place the cauliflower in a steamer basket on top of a pot with boiling water and steam until fork-tender, around 6-7 minutes. (Alternatively, purchase frozen cauliflower florets and cook in the microwave according to package directions). Remove from heat (or microwave). Remove from heat and transfer cauliflower into a cold water bath to prevent further cooking. Drain well and pat dry.
Transfer steamed cauliflower to a large bowl and add cream cheese, heavy cream, butter, garlic powder, and dried dill. Season with salt and black pepper, to taste, and toss to combine.
Transfer to oven-safe casserole dish and top with shredded cheese blend and crumbled bacon. Place in pre-heated oven and roast until cheese is melted and nicely browned on top, around 8-10 minutes.
Remove from oven and serve immediately topped with fresh chives.