Step 1

Preheat oven to 400°F. Coat a 7-by-11-inch (2-quart) baking dish with cooking spray.

Step 2

Place cauliflower in a microwaveable bowl. Cover tightly and microwave on High until tender, about 3 minutes. Drain, if necessary.

Step 3

Combine cream cheese, garlic powder, onion powder, oregano, mustard, pepper, salt, cayenne and ¼ cup scallions in a large bowl; beat with an electric mixer on medium speed until smooth, about 1 minute. Fold in the cauliflower, chicken and 1 cup Cheddar. Spoon the mixture into the prepared baking dish. Sprinkle with the remaining ½ cup Cheddar and cover with foil.

Step 4

Bake until bubbly, about 30 minutes. Uncover and bake until the cheese browns, about 10 more minutes. Remove from oven and sprinkle with the remaining ¼ cup scallions. Let stand for 10 minutes before serving.