Step 1

Preheat oven to 400 degrees F (200 degrees C). Grease a large, square baking dish with cooking spray.

Step 2

Put cauliflower in a microwave-safe bowl and cook in microwave oven until tender, about 6 minutes.

Step 3

Blend cauliflower in a food processor until smooth; add sour cream, yogurt, and butter and process again until smooth.

Step 4

Mix blended cauliflower mixture in a bowl with 3/4 cup Cheddar cheese, bacon bits, chives, garlic, and black pepper; spread into the prepared baking dish and top with remaining Cheddar cheese.

Step 5

Bake in preheated oven on the middle rack until cheese is melted, about 15 minutes. Switch oven to 'broil' and continue baking until the top is golden brown, 3 to 5 minutes more.