Angus Beef Tenderloin With Japanese Sweet Potato And Maitake Mushrooms Recipe

Prepare and Season

Remove the tenderloin from the refrigerator 30–45 minutes before cooking to come toward room temperature. Pat dry with paper towels. Tie with kitchen twine if not already tied to ensure even cooking. Generously season all sides with kosher salt and freshly ground black pepper, pressing the salt into the meat.

Sear

Preheat oven to 425°F (220°C). Heat a heavy ovenproof skillet (cast iron preferred) over high heat until smoking slightly. Add 2 tbs neutral oil, swirl to coat. When oil shimmers, add the tenderloin and sear without moving for 2–3 minutes until deeply browned. Rotate to brown all sides, about 6–8 minutes total.

Finish in Oven with Baste

Reduce heat to medium-high, add 2 tbs unsalted butter, thyme sprigs, and smashed garlic to the pan. Tilt the pan and spoon melted butter over the tenderloin for 1 minute. Transfer skillet to the preheated oven and roast until internal temperature reaches 125°F (52°C) for medium-rare (about 12–18 minutes depending on thickness). Start checking with an instant-read thermometer at 10 minutes.

Rest

Remove tenderloin to a cutting board, tent loosely with foil, and rest for 10–12 minutes; carryover will bring it to about 130°F (54°C). Reserve any pan juices for the mushrooms or to spoon over slices when serving.

Cook Sweet Potatoes

Place the peeled and cut sweet potato chunks in a medium saucepan and cover with cold water by 1 inch. Add a pinch of salt. Bring to a boil over high heat, then reduce to a simmer and cook until very tender, 12–15 minutes. Drain well.

Mash and Season

Return hot potatoes to the warm saucepan or a bowl. In a small saucepan, heat the milk with 2 tbs butter just until the butter melts and the milk is warm (do not boil). Mash the potatoes using a potato masher or ricer until smooth, gradually adding the warm milk-butter mixture until you reach a silky, spreadable consistency. Stir in 1 tsp white miso, 1 tsp salt (adjust to taste), and 1/2 tsp freshly ground black pepper. Taste and adjust seasoning.

Keep Warm

Cover and keep the purée warm on the lowest heat or in a warm oven (about 200°F / 95°C) while finishing mushrooms and resting the beef. If the purée tightens, stir in a splash of warm milk to loosen.

Prepare Pan

While the beef rests, heat a large skillet over medium-high heat. Add 1 tbs extra-virgin olive oil and 1 tbs unsalted butter. When the butter has melted and the pan is hot, add the minced shallot and sauté for about 1 minute until translucent.

Sauté Mushrooms

Add the torn maitake mushrooms to the skillet in an even layer. Let them brown undisturbed for 2–3 minutes, then stir and continue cooking until golden and slightly crisp at the edges, 3–4 more minutes. Stir in the minced garlic and cook 30–45 seconds until fragrant.

Deglaze and Season

Pour in 2 tbs dry white wine or sherry to deglaze the pan, scraping up any brown bits and the reserved pan juices from the beef if you have them. Allow the liquid to reduce by half (about 1–2 minutes). Stir in 1 tsp low-sodium soy sauce and 1 tsp fresh lemon juice; cook another 30 seconds. Taste and finish with 1/2 tsp flaky sea salt if needed.

Finish and Garnish

Remove from heat, stir in chopped fresh chives, and spoon any mushroom juices over the rested tenderloin when serving.