Prepare the Vegetables: The Veggie Prep: Preheat oven to 375°F (191°C). If using frozen spinach: Thaw completely and squeeze out as much excess water as possible. This is absolutely crucial to prevent a watery casserole. You can use your hands, a clean kitchen towel, or even a potato ricer to remove the water. If using fresh broccoli: Boil for 1–2 minutes until bright green and slightly tender-crisp, then drain well. Pro Tip for Perfectly Cooked Broccoli: Slightly undercooking the broccoli during the pre-boil will ensure it doesn’t become mushy during baking. You want it to retain some of its texture.

Combine the Main Ingredients: The Flavor Fusion: In a large bowl, combine the cooked chicken, chopped bacon, prepared vegetables, minced garlic, ranch dressing, mozzarella cheese, and cheddar cheese. Mix well to ensure all the ingredients are evenly distributed and thoroughly coated in the dressing. Add the optional ranch seasoning mix if desired. Pro Tip for Easy Mixing: You can also mix all the ingredients directly in the casserole dish to save on dishes, especially if you’re using a large enough dish. This is a great time-saving trick, especially on busy weeknights.

Transfer to Casserole Dish: The Dish Designation: Transfer the mixture to a 9×13 inch (23×33 cm) casserole dish. Pro Tip for Easy Serving: Lightly greasing the casserole dish with cooking spray or a little olive oil will make it easier to serve the casserole and prevent it from sticking to the bottom.

Add the Cheese Topping: The Cheesy Charm: Sprinkle the remaining mozzarella and cheddar cheeses evenly over the top of the casserole. Pro Tip for a Crispy Topping: For an extra crispy and golden-brown topping, you can broil the casserole for the last minute or two of baking. Keep a close eye on it to prevent burning.

Bake and Serve: The Final Act: Bake for about 15 minutes, or until the top is hot, bubbly, and lightly golden brown. The cheese should be melted and slightly browned. Remove from oven, let cool slightly for a few minutes, then serve. Pro Tip for Serving: Letting the casserole cool slightly will allow it to set a bit, making it easier to serve and preventing it from being too runny.