First Step: Preheat and Prep Start by preheating your oven to 400°F (200°C) to ensure even baking. While the oven heats, gather and measure all ingredients this mise en place makes your quick broccoli chicken casserole assembly smoother. For gluten-free adaptations, swap in gluten-free pasta here to keep things seamless.

Second Step: Cook the Pasta and Broccoli Cook 8 oz of pasta in a large pot of generously salted boiling water until al dente, which takes about 8-10 minutes. Add the broccoli florets from 1 large head one minute before the pasta is done, so they steam perfectly. Drain everything together; this step infuses your healthy broccoli chicken casserole with vibrant green goodness and saves time.

Third Step: Sauté the Vegetables In a large sauté pan, heat 2 Tbsp of butter or olive oil over medium-high heat. Add 1 small sliced onion and sauté for about 3 minutes until softened, then toss in 8 oz of sliced mushrooms and 4 minced garlic cloves. Cook for another 5 minutes until tender this builds flavor for your low-fat broccoli chicken casserole while keeping it light.

Fourth Step: Make the Sauce Sprinkle 3 Tbsp of flour over the veggies and stir for 1 minute to create a roux. Gradually whisk in 1 cup of stock, followed by 1½ cups of milk, 1 tsp of Dijon mustard, ½ tsp of salt, and ¼ tsp of pepper. For a low-calorie version, use low-fat milk here. Simmer for 2-3 minutes until thickened, then remove from heat and mix in 1 cup of shredded cheddar until melted, creating a creamy base for your broccoli chicken bake.

Fifth Step: Combine and Bake In a 9×13-inch baking dish, mix the cooked pasta, broccoli, 2 cups of cooked chicken, and the cheese sauce. Toss everything evenly and spread into a layer. Bake uncovered for 15 minutes at 400°F. For the final touch, add the remaining 1 cup of cheddar on top and bake for another 10 minutes until golden and bubbly, resulting in a delicious healthier broccoli chicken casserole.

Sixth Step: Serve and Enjoy Once baked, let it cool slightly before serving warm. Garnish with extra black pepper or fresh herbs if desired this step makes your easy broccoli chicken casserole even more appealing. Remember, for vegan swaps, use plant-based cheese to adapt as needed, keeping the dish versatile and nutritious.