Step 1: Preheat the Oven

• Preheat your oven to 375°F (190°C). Grease a 9×13-inch casserole dish with nonstick cooking spray and set aside.

Step 2: Blanch the Broccoli

• Bring a large pot of water to a boil. Add the broccoli florets and blanch for 2-3 minutes, just until they turn bright green. Drain and immediately transfer the broccoli to a bowl of ice water to stop the cooking process. Drain well and pat dry with a clean kitchen towel.

Step 3: Prepare the Creamy Sauce

• In a large mixing bowl, combine the cream of chicken soup, sour cream, mayonnaise, and chicken broth. Stir until smooth and well blended.
• Add the Dijon mustard, garlic powder, onion powder, smoked paprika, salt, and black pepper. Mix thoroughly to combine, creating a creamy, flavorful base for the casserole.

Step 4: Assemble the Casserole

• Add the shredded chicken and blanched broccoli florets to the creamy sauce mixture. Stir until everything is evenly coated.
• Transfer the mixture to the prepared casserole dish and spread it out evenly. Sprinkle the shredded cheddar cheese over the top, ensuring the entire surface is covered with a layer of gooey cheese.

Step 5: Make the Garlic Herb Panko Topping

• In a small bowl, combine the panko bread crumbs, melted butter, grated Parmesan, chopped parsley, garlic powder, thyme, and oregano. Stir until the panko is well-coated with the herb-infused butter mixture.

Step 6: Add the Topping and Bake

• Sprinkle the garlic herb panko mixture evenly over the cheese layer in the casserole dish.
• Place the casserole in the preheated oven and bake for 25-30 minutes, or until the top is golden brown and the cheese is bubbly around the edges.

Step 7: Let It Cool and Serve

• Remove the casserole from the oven and let it rest for 5-10 minutes before serving. This will allow the flavors to meld and the sauce to thicken slightly.