Preheat a heavy skillet (cast-iron preferred) over medium-high heat until smoking point is near. Add 1 tablespoon unsalted butter and swirl to melt and foam.

Sear steak for 3–4 minutes per side for medium-rare (internal temperature 130–135°F / 54–57°C). If steak is thick, sear edges 30–60 seconds. Spoon pan juices over steak while cooking.

Remove steak to a cutting board, tent loosely with foil and rest for 8–10 minutes before slicing across the grain into 1/4–1/2" slices.

Fingerling Potatoes

While steak rests, preheat oven to 425°F (220°C) if not already hot. Halve or leave small fingerlings whole so pieces are roughly 1–1.5 inches.

Toss fingerlings with 1 tablespoon olive oil, fresh thyme leaves, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper on a rimmed baking sheet in a single layer.

Roast in oven 20–25 minutes until fork-tender and golden, turning once halfway through. Alternatively, pan-roast in the hot skillet for 12–15 minutes, stirring occasionally, until crisp and tender.

Broccolini

Trim broccolini stems if thick. Thinly slice garlic clove.

In a medium sauté pan over medium heat, warm 1 tablespoon olive oil. Add garlic and red pepper flakes and cook 30–45 seconds until fragrant but not browned.

Add broccolini and 2–3 tablespoons water, cover and steam for 2–3 minutes until bright green and tender-crisp. Remove cover and continue to cook 1–2 minutes to evaporate excess moisture.

Season with 1/4 teaspoon kosher salt, squeeze juice from 1/2 lemon over broccolini, toss, and remove from heat.

Red Wine Jus

Mince shallot. In the skillet used for steak (leave fond and any rendered juices), reduce heat to medium and add 1 tablespoon butter. Add shallot and cook 1–2 minutes until softened.

Carefully pour in 1/2 cup dry red wine to deglaze, scraping up browned bits. Increase heat and simmer until wine is reduced by about half, 3–5 minutes.

Add 1 cup beef stock, 2 sprigs fresh thyme and 1 bay leaf. Simmer gently 6–8 minutes to concentrate flavors. Remove thyme stems and bay leaf.

Swirl in remaining 1 tablespoon butter off heat to enrich the sauce. Season with 1/4 teaspoon salt and 1/8 teaspoon black pepper, tasting and adjusting.

If a slightly thicker jus is desired, make a slurry of 1/2 teaspoon cornstarch and 1 tablespoon cold water, whisk into simmering jus and cook 1 minute until glossy and slightly thickened.

Plating & Finish

Arrange roasted fingerlings and broccolini on plates. Fan slices of rested hanger steak over or beside vegetables.

Spoon 2–3 tablespoons of red wine jus over the steak and a little around the plate. Sprinkle chopped parsley and a pinch of flaky sea salt over steak and vegetables.

Serve immediately while hot.