Bring a large pot of salted water to a rolling boil. Add elbow macaroni and cook until al dente, about 7-9 minutes. Drain and set aside.

In a large skillet over medium heat, melt 2 tablespoons of butter. Add cubed chicken breasts seasoned with salt and pepper. Cook for about 5-7 minutes until golden brown and cooked through. Remove from skillet and set aside.

Using the same skillet, melt 2 tablespoons of butter over medium heat. Whisk in 2 tablespoons of flour for about 1-2 minutes until smooth. Gradually whisk in 2 cups of milk, cooking until thickened, about 4-5 minutes.

Lower heat to medium-low and add 2 cups of shredded cheddar cheese, stirring until melted and creamy.

Fold in the cooked macaroni and sautéed chicken until evenly coated with cheese sauce.

For a crunchy topping, transfer to an oven-safe dish, sprinkle with breadcrumbs, and bake at 350°F (175°C) for about 20 minutes until golden brown.

Serve warm, garnished with parsley.