Leftover Beef Tenderloin Sandwiches require very few add-ons to elevate already tender slices of fabulously flavored filet mignon roast.

As if a whole beef tenderloin roast isn’t fabulous enough, the leftovers of such a masterpiece are equally as spectacular sliced thin and piled high atop fresh toasty rolls! Layer with room temperature roasted peppers, sour cream horseradish sauce, and warm beef broth au jus for my personal moment of culinary genius.

Hungry for the whole beef tenderloin roast that proceeded this luscious sandwich? I’ve got you covered when it comes to this succulent cut of beef and the method to go with it!

Ingredients for Leftover Beef Tenderloin Sandwiches

• roasted red bell peppers
• horseradish cream or prepared horseradish sauce
• sub rolls
• olive oil
• salted butter
• leftover beef tenderloin roast, leftover prime rib roast, or leftover roast beef
• Kosher salt
• black pepper
• homemade au jus or beef broth

optional

• caramelized or raw red onion
• caramelized or raw sweet onion
• sauteed mushrooms
• provolone cheese, Havarti cheese, crumbled goat cheese, or other cheese of choice

How to Make Tenderloin Sandwiches

Gauge the Amount of Leftover Beef on Hand

The best way to maximize the size of each sandwich is to consider the size of the leftover beef roast you will be working with. Three cups of thinly sliced beef are enough for four modest sandwiches and can make the perfect meal with a few pantry flavor additions.

That said, more tender slices of beef are never wrong. Be your own judge based on what you like and what your eaters will eat. You know…go big or go home as they say.

Prepare the Rolls

Preheat your oven to 225°F. Line a large, rimmed baking sheet with aluminum foil and set aside.

In a small saucepan, brown some salted butter. Cook over medium-low heat until it’s golden brown and offers a sweet and nutty aroma, about 4 to 6 minutes. Add a splash of Worcestershire sauce, stir, and remove from heat.

Use a sharp serrated bread knife to split the rolls. I split down one side and through the middles leaving me with “boats” to catch all the juices.

Use a pastry brush to baste both inside halves of the roll. Use just enough to help to both flavor and to coat the cut sides.

Any leftover brown butter will be used to baste the beef directly once it’s loaded into the rolls. This adds flavor to that first bite and every bite thereafter.

Prepare the Tenderloin

For the absolute best results, slice your tenderloin while the roast is cold. Use a sharp kitchen knife and carefully use your finger as a guide keeping it at a 90° angle so you do not accidentally cut yourself.

Cut paper-thin slices of roast until you’ve got enough for the sandwiches. Drain some roasted red bell peppers on paper toweling and use a sharp knife to julienne them into long strips.

In a large cast iron skillet, heat some quality olive oil over medium-high heat. Once shimmering, add the beef and season with course ground salt and black pepper.

If serving with au jus, ladle some beginning with 1/2-cup measure into the pan and immediately and add a tablespoon of butter. Use beef broth instead of au jus, if necessary, followed by butter.

Turn the burner to low merely to keep the beef warm while you toast the rolls.

Assembling the Sandwiches

Place each open roll onto the prepared baking sheet and into the preheated oven for 4 to 6 minutes. The rolls should be warm but still soft to the touch.

Remove from the oven and spoon some horseradish cream (or prepared jarred horseradish sauce) on the inside of one half of each roll. Offer additional tableside.

Use the kitchen tongs to load each sub roll generously with slices of the tenderloin. Layer with strips of the julienned roasted peppers.

It’s at this point that any additional topping(s) you want to add should be added. Because tender beef boasts intense flavor all on its own, allow the meat to be the star of the show, being careful to choose add-ons that won’t obstruct the flavor of the beef.

Brush whatever brown butter remains over the exposed beef. Slice each sandwich in half on a severe diagonal and arrange both halves on a plate.

Offer PLENTY of napkins and eat up. This is such a great way to make use of those leftovers and fill hungry bellies at the same time.