Place the frozen cauliflower in a 1 1/2-quart casserole. Add 1/2 cup water. Cover and microwave on high for 7 minutes. Stir and cook another 4 minutes. Let stand 2 minutes. Place in a colander to drain and blot with paper towels to absorb as much moisture as possible.
Place the cauliflower in a food processor. Add the sour cream, cream cheese, butter, half the cheese, half the bacon, salt and pepper to processor. Process until contents have the smooth consistency of mashed potatoes.
Grease the same casserole used for cooking the cauliflower and pour in the cauliflower mixture.
Top with the remaining cheese and crumbled bacon.
Bake uncovered 20 minutes at 400º or until lightly browned.