Tenderloin Recipe

Make the compound butter

In a medium bowl, combine softened unsalted butter (6 tbs) with 1 tbsp prepared horseradish, 1 tbsp finely chopped chives, 1/2 tsp lemon juice, 1/4 tsp kosher salt and 1/8 tsp freshly ground black pepper. Mix thoroughly until uniform. Taste and adjust horseradish or salt. Transfer butter to plastic wrap, shape into a log, wrap tightly and chill in refrigerator while you prepare the rest; roll can chill at least 30 minutes to firm. If you prefer a slab, press into a small dish and refrigerate.

Cook sweet potatoes

Place peeled, cubed sweet potatoes (about 1.25 lb) in a medium pot and add cold water to cover by 1 inch. Add a pinch of salt. Bring to a boil over high heat, then reduce to a simmer and cook until tender, 12–15 minutes (a fork should slide easily through). Drain well in a colander and return potatoes to the pot off the heat for 1–2 minutes to let residual moisture evaporate.

Mash and season

Add 2 tbs unsalted butter to the hot potatoes and mash with a potato masher or fork until mostly smooth. Stir in 2 tbs pure maple syrup, 3 tbs milk, 1/4 tsp cayenne pepper, 1/4 tsp ground cinnamon, 1/2 tsp kosher salt and 1/4 tsp freshly ground black pepper. Adjust milk for desired creaminess and maple or cayenne to taste. Keep warm over low heat or cover and set aside in a warm spot while you grill the beef and asparagus.

Bring steaks to temperature and season

Remove the tenderloin filets from the refrigerator 30–45 minutes before cooking to come toward room temperature. Pat dry with paper towels. Rub each filet lightly with 1 tbs olive oil (total 2 tbs) and season both sides with kosher salt (about 1 tsp total) and freshly ground black pepper (about 1 tsp total).

Preheat grill or pan

If using a grill, preheat to high heat (450–500°F / 230–260°C) with one zone for direct searing and an indirect zone. If using a heavy skillet (cast-iron), heat over medium-high until smoking hot and add 1 tbs oil and 1 tbs butter just before searing.

Sear and finish

Sear filets 2–3 minutes per side on the hot direct heat to develop a brown crust. If using a grill with indirect zone, after searing move filets to indirect heat and close lid to finish. Target internal temperatures: rare 120–125°F (49–52°C), medium-rare 130–135°F (54–57°C), medium 140–145°F (60–63°C). Finish will depend on thickness—expect 4–8 minutes after sear for medium-rare. Use an instant-read thermometer at the thickest part to check doneness.

Rest

Transfer filets to a cutting board and loosely tent with foil. Rest 5–8 minutes to allow juices to redistribute.

Finish with butter

Slice a 1/2-inch medallion from the chilled horseradish & chive butter log and place on top of each hot filet to melt just before serving (or serve slices alongside).

Prep and grill asparagus

While steaks rest or during final minutes of cooking, toss trimmed asparagus (1 lb) with 1 tbs olive oil, 1/2 tsp kosher salt and 1/4 tsp freshly ground black pepper. Place asparagus on the hot grill perpendicular to the grates or in a grill basket. Grill 2–4 minutes, turning occasionally, until tender-crisp and charred in spots. If using a skillet, cook 4–6 minutes over medium-high heat, turning frequently.

Finish

Remove from heat, optionally squeeze half a lemon over the asparagus, and transfer to serving plates.

Divide the maple-cayenne sweet potato mash between two plates (or four if serving smaller portions). Place a rested filet on each plate. Top each filet with a slice of horseradish & chive butter so it melts over the meat. Arrange the grilled asparagus alongside. Spoon any resting juices from the cutting board over the steaks if desired. Serve immediately.