– 8 oz elbow macaroni – 3 Tbsp unsalted butter – 2 Tbsp all-purpose flour – 2 ½ cup milk – 2 slices American cheese – 8 oz cheddar cheese – 2 tsp Dijon mustard – ½ tsp kosher salt – 1 pinch cracked pepper – ½ cup buttery crackers – ¼ cup parmesan cheese