Start by trimming any excess fat off the beef tenderloin.

Rub the tenderloin with olive oil, salt, and pepper.

Heat your grill or skillet over medium-high heat.

Place the tenderloin on the grill or skillet and cook for about 5-7 minutes on each side until it reaches your desired doneness.

Remove the tenderloin from heat and let it rest for 5 minutes.

Using a sharp knife, slice the tenderloin against the grain into thin pieces.

Spread mayonnaise and Dijon mustard on the sandwich buns.

Layer the sliced tenderloin, lettuce, and tomato on the buns.

Close the sandwich and serve immediately.