Preheat your oven to 350°F and spray a 9x9 inch baking dish with cooking spray, making sure to coat the bottom and sides evenly. While the oven heats, if you haven't already cooked your chicken and bacon, do so now—you'll need 4.5 cups of shredded or diced cooked chicken and about 8 slices of bacon cooked until crispy, then crumbled. Having everything prepped and ready before you start assembling will make the next steps quick and seamless.

In a large bowl, combine the cooked chicken, ranch seasoning mix, cheddar cheese, crumbled bacon, sour cream, cream of chicken soup, and softened cream cheese. Mix everything together thoroughly until well combined and creamy—I like to use a sturdy wooden spoon or spatula to work through the mixture, making sure the cream cheese is fully incorporated and there are no lumps. The mixture should be uniform and cohesive before transferring to the baking dish.

Pour the creamy chicken mixture from Step 2 into the prepared 9x9 inch baking dish and spread it out evenly into a single layer. Make sure it's distributed evenly across the bottom so it bakes uniformly and creates an even thickness throughout the casserole.

In a small bowl, combine the crushed Ritz crackers with the melted butter, stirring until the crackers are evenly coated and the mixture resembles coarse breadcrumbs. Sprinkle this cracker mixture evenly over the top of the casserole. I find that crushing the crackers by hand into finer pieces (rather than leaving large chunks) helps them toast more evenly and creates a better textured crust.

Place the casserole in the preheated 350°F oven and bake for 30 to 40 minutes, until the top is golden brown and the edges are bubbling slightly. The casserole is done when you can see the creamy mixture bubbling around the edges and the cracker topping has turned a deep golden color. Let it rest for 5 minutes before serving—this helps it set slightly and makes it easier to portion.