# The Ingredients You'll Need:
→ Protein & Vegetables
01 - 2 cups cooked chicken breast, diced or shredded
02 - 3 cups fresh broccoli florets
→ Sauce & Base
03 - 2 tablespoons unsalted butter
04 - 2 tablespoons all-purpose flour
05 - 1 cup whole milk
06 - 1/2 cup low-sodium chicken broth
07 - 1 teaspoon Dijon mustard
08 - 1/2 teaspoon garlic powder
09 - 1/2 teaspoon onion powder
10 - 1/2 teaspoon salt
11 - 1/4 teaspoon black pepper
→ Cheese & Topping
12 - 1 1/2 cups sharp cheddar cheese, shredded (divided)
13 - 1/2 cup panko breadcrumbs
14 - 1 tablespoon olive oil
→ Optional
15 - 1/4 teaspoon crushed red pepper flakes
# Step-by-Step Instructions:
01 - Preheat oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish to prevent sticking.
02 - Steam or blanch the broccoli florets in boiling water for 2 to 3 minutes, until just tender and vivid green. Drain well and reserve.
03 - Melt butter in a medium saucepan over medium heat. Stir in flour, cooking for 1 minute while whisking constantly until combined.
04 - Gradually whisk in milk and chicken broth, stirring to prevent lumps. Cook 3 to 4 minutes until thickened. Blend in Dijon mustard, garlic powder, onion powder, salt, and black pepper. Remove from heat and stir in 1 cup shredded cheddar cheese until smooth.
05 - In a large mixing bowl, combine cooked chicken, blanched broccoli, and the cheese sauce, folding until uniformly coated.
06 - Distribute mixture evenly in the prepared baking dish.
07 - Sprinkle remaining 1/2 cup cheddar cheese across surface. In a separate bowl, toss panko breadcrumbs with olive oil and the optional red pepper flakes, then scatter atop the casserole.
08 - Bake for 25 to 30 minutes until bubbling and topping is golden brown.
09 - Allow casserole to cool for 5 minutes prior to serving for optimal texture.
