Smoked Roasted Tenderloin of Beef over Blue Cheese Potato Gratin, Charred Broccolini, Crispy Leeks, Sherry Caramelized Onion Butter and House Demi Recipe

Prep and assemble

Preheat oven to 375°F (190°C). Butter a 9x6" or similar shallow gratin dish with 1 tablespoon butter. Place sliced potatoes in a bowl and season with 1 tsp salt, 1/2 tsp black pepper and the minced garlic. In a saucepan, combine heavy cream and whole milk and warm gently until just simmering; remove from heat and stir in thyme and half (2 oz) of the crumbled blue cheese so it begins to melt into the cream.

Layer and bake

Arrange a single overlapping layer of potato slices in the gratin dish. Spoon some of the warm blue-cheese cream over the layer. Repeat layering until all potatoes are used, finishing with the remaining cream. Crumble remaining blue cheese and sprinkle Parmesan on top. Cover tightly with foil and bake 35 minutes, then remove foil and bake another 15–20 minutes until potatoes are tender and top is golden and bubbling. Let rest 10 minutes before slicing into portions.

Season and cold-smoke

Pat the tenderloin dry and season all over with 2 tsp kosher salt and 1 tsp freshly ground black pepper. Rub with 2 tbs olive oil. Preheat a smoker or grill for indirect smoking to 225°F (107°C) with soaked wood chips added for fragrant smoke. Place the tenderloin on the smoker/grill and cold-smoke/slow-smoke until internal temperature reaches 110°F (43°C) for medium-rare target finish, about 45–60 minutes depending on size. Remove from smoker and let rest briefly.

Roast to finish

Preheat oven to 450°F (232°C). Heat a heavy ovenproof skillet over high heat until smoking. Sear the smoked tenderloin in the skillet 1–2 minutes per side to develop a crust. Transfer skillet to the hot oven and roast until internal temperature reaches 125°F (52°C) for medium-rare (about 6–10 minutes depending on thickness). Remove and rest 8–10 minutes, then finish by brushing with 2 tbs room-temperature butter to gloss the surface and keep warm.

Blanch broccolini in salted boiling water for 1 minute until bright green, then immediately plunge into ice water to stop cooking. Pat dry. Toss with 1 tbs olive oil, 1/2 tsp salt and lemon zest. Heat a cast-iron skillet or grill pan until very hot, then char broccolini in batches 1–2 minutes per side until tips and edges have good char marks but stems remain crisp-tender. Keep warm.

Heat neutral frying oil in a deep skillet or small pot to 350°F (175°C). Toss julienned leeks with 1/2 cup flour and 1/2 tsp sea salt until lightly coated. Shake off excess flour and fry in batches for 30–60 seconds until golden brown and crisp. Remove with a slotted spoon to a paper towel-lined tray and season immediately with a pinch of sea salt. These can be made ahead and kept on a rack in a low oven (200°F / 95°C) to stay crisp.

Melt 3 tbs unsalted butter in a skillet over medium-low heat. Add thinly sliced yellow onion and 1/4 tsp sugar with a pinch of salt. Cook slowly, stirring occasionally, until onions are deeply golden and caramelized, about 18–22 minutes. Add 3 tbs dry sherry and increase heat to medium to reduce and glaze the onions, about 2–3 minutes. Stir in 1/2 tsp chopped thyme and remove from heat. Whisk or mash the caramelized onions into 2 tbs room-temperature butter until combined into a spreadable compound butter. Keep warm or refrigerate briefly and re-warm before serving.

In a small saucepan over medium heat, melt 1 tbsp butter and add minced shallot; sweat until translucent about 2 minutes. Pour in 1/4 cup red wine and reduce by half. Add 1 cup demi-glace (or reduced beef stock) and simmer gently until slightly thickened, about 6–8 minutes. Whisk in 1 tbsp cold butter off the heat to finish and season with 1/4 tsp black pepper. Keep warm in a small sauce pot.

Slice the rested tenderloin into 1" medallions. Spoon a generous portion of warm blue cheese potato gratin onto the center of each plate. Fan 3–4 tenderloin medallions over the gratin. Arrange 3–4 charred broccolini stalks alongside. Spoon 1–2 tbs warmed demi-glace around the meat (not over the crispy leeks). Place a small quenelle or spoonful (about 1 tbs) of sherry caramelized onion butter atop the meat so it melts. Scatter a small handful (about 1–2 tbs) of crispy leeks over the top for crunch. Finish with a pinch of sea salt flakes and 2 tsp microgreens or chives per plate. Serve immediately.