Step 1

Preheat oven to 425°F. Coat a 13- x 9-inch baking dish with cooking spray. Set aside.

Step 2

Fit a large pot with a steamer basket, and fill with 1 inch of water. Add cauliflower florets, and cover. Bring to a boil over medium-high. Reduce heat to medium, and steam until cauliflower is very tender, about 20 minutes. Remove from heat, and let stand 5 minutes.

Step 3

Meanwhile, stir together cream cheese and sour cream in a large bowl until very smooth, about 1 minute. Fold in garlic powder, 1 cup each of the Cheddar and pepper Jack, half of the bacon, and 3 tablespoons of the chives. Fold in warm cauliflower. Spoon into prepared baking dish. Sprinkle with remaining bacon, Cheddar, and pepper Jack.

Step 4

Bake in preheated oven until cheese is melted and top starts to brown, 15 to 20 minutes. Sprinkle with remaining 1 tablespoon chives. Serve hot.