Preheat your oven to 350°F (175°C). Grease the baking dish with butter to prevent the macaroni pie from sticking.

Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to the package instructions until al dente. Drain the pasta in a colander and set aside.

In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook, stirring constantly, until the mixture is smooth and bubbly. Gradually whisk in the milk, continuing to stir until the sauce thickens and comes to a gentle boil.

Remove the saucepan from the heat and stir in 3 cups of the grated cheddar cheese until melted and smooth. Add the kosher salt, black pepper, and Italian seasoning, stirring to combine.

In a large mixing bowl, combine the cooked elbow macaroni with the cheese sauce, stirring until the pasta is evenly coated.

Pour the macaroni and cheese mixture into the prepared baking dish. Sprinkle the remaining cup of grated cheddar cheese evenly over the top, followed by the Italian seasoned bread crumbs.

Bake in the preheated oven for 25-30 minutes, or until the top is golden and bubbly.

Remove the macaroni pie from the oven and let it cool for at least 10 minutes before serving. This allows the cheese to set slightly, making it easier to slice and serve.