Classic Roast Beef Sandwich with Au Jus

Method

1. Preheat oven to 350°F (175°C).
2. Spread mayonnaise and Dijon mustard on the bread slices.
3. Layer the roast beef slices on the bottom bread slice.
4. Pour au jus sauce over the roast beef.
5. Top with the second bread slice and press gently.
6. Heat a skillet over medium heat, add butter, and cook the sandwich until golden brown.
7. Serve with crispy fries on the side.
8. For whole cuts, check a minimum internal temperature of 63°C (145°F), then rest for at least 3 minutes before serving.