Follow these detailed instructions to ensure your sliders come out perfectly baked, with a gooey center and a golden, buttery top. The process is straightforward and rewarding.

Step 1: Preheat Oven and Prepare Baking Dish
First, position a rack in the center of your oven and preheat it to 350°F (175°C). Lightly grease a 9×13-inch baking dish with non-stick spray or a thin layer of butter. This will prevent the sliders from sticking and make cleanup much easier.

Step 2: Create the Creamy Chicken Filling
In a large mixing bowl, combine the softened cream cheese, mayonnaise, and sour cream. Using a hand mixer on low speed or a sturdy spatula, beat these ingredients together until the mixture is completely smooth and free of any lumps. This creamy base is essential for the dip’s texture. Next, add the shredded chicken, sharp cheddar cheese, Monterey Jack cheese, grated Parmesan cheese, finely sliced green onions, garlic powder, onion powder, and black pepper to the bowl. Switch to a spatula or large spoon and fold everything together until all the ingredients are evenly distributed. Take a moment to taste the mixture and adjust seasonings if needed.

Step 3: Prepare the Slider Rolls
Take your slab of 12 slider rolls and, without separating them, use a large serrated bread knife to carefully slice the entire slab in half horizontally. You should have one large top piece and one large bottom piece. Place the entire bottom slab of rolls into your prepared 9×13-inch baking dish.

Step 4: Assemble the Sliders
Spoon the prepared chicken and cheese dip filling evenly over the bottom slab of rolls. Use the back of the spoon or an offset spatula to spread the mixture all the way to the edges, ensuring every slider gets a generous amount of filling. Once the filling is evenly spread, place the top slab of rolls directly on top, lining it up with the bottom.

Step 5: Prepare the Savory Butter Topping
In a small, microwave-safe bowl, melt the 4 tablespoons of unsalted butter. Once melted, stir in the minced fresh parsley and the Worcestershire sauce. Mix well until everything is combined. This simple topping is what transforms the sliders, creating a crisp, golden-brown crust and infusing the bread with flavor.

Step 6: Brush and Bake
Using a pastry brush, generously brush the entire surface of the top slab of rolls with the melted butter mixture. Make sure to get into all the crevices between the individual rolls. This ensures every bite is buttery and delicious. Now, cover the baking dish loosely with aluminum foil. The foil will trap steam, helping the cheese melt completely without the tops of the rolls burning.

Step 7: Bake to Golden Perfection
Place the foil-covered baking dish into the preheated oven and bake for 15 minutes. After 15 minutes, carefully remove the aluminum foil. The tops of the rolls will look pale but the cheese inside will be starting to melt. Return the dish to the oven, uncovered, and bake for another 10-15 minutes, or until the tops of the sliders are a deep golden brown and the cheese filling is hot and bubbly around the edges.

Step 8: Rest, Slice, and Serve
Once baked, remove the sliders from the oven and let them rest in the baking dish for at least 5 minutes. This crucial step allows the melted cheese and filling to set slightly, making the sliders much easier to cut and serve without falling apart. After resting, use a sharp knife or a bench scraper to cut along the lines of the individual rolls to separate them. Serve immediately while they are warm and gooey.