Optional: Place one tray on the second or third rack from the top of the oven on high broil. Spray a large 13" x 9" casserole dish with cooking spray. Spread cauliflower cheesy mixture in baking dish. I add 1–2 cups cheese to cauliflower.
3–5 minutes, broil cheese until melted and golden brown. Chopped crispy bacon and chives go with baked mac and cheese. Serving baked cauliflower mac and cheese with your main!