Step 1

Preheat oven to 350 degrees F. Lightly grease a 9- by 13-inch baking dish.

Step 2

In a large bowl, combine the mayonnaise, milk, ranch mix, red pepper flakes, and black pepper until well blended.

Step 3

Add the cooked pasta, chicken, broccoli, half the cheeses and half of the bacon, and mix until well combined.

Step 4

Spread mixture evenly in the prepared baking dish.(Cover and refrigerate now if you're making ahead.)

Step 5

Bake, uncovered, until hot, about 25 minutes.

Step 6

Remove from the oven and sprinkle with the remaining cheeses and bacon. Return to the oven and bake, uncovered, until cheese melts and mixture is hot and bubbling, about 10 more minutes.

Step 7

Serve topped with halved tomatoes and green onion.