Directions

1. In a large saucepan over medium heat, melt the butter. Gradually stir in the flour until it's a smooth, thick paste.
2. Slowly add the milk (small amounts at a time), whisking constantly until it's smooth. Once it begins to thicken, add in the cheese and stir continually until it's smooth and creamy. Mix in the mustard, salt and pepper.
3. Add the cheese mixture to the bowl of macaroni and stir until it's well-coated.
4. Butter a 9x13 baking dish and transfer the macaroni and cheese to it.
5. In a small saucepan, melt the butter, then add in the breadcrumbs and parsley and mix until coated. Spread the breadcrumbs on top of the macaroni.
6. Bake in a 375-degree oven for approximately 30 minutes (until the breadcrumbs are brown).