Remove the 10oz dry-aged sirloin steaks from the refrigerator 30–45 minutes before cooking so they come to room temperature. Pat dry thoroughly with paper towel.

Season steaks

Just before cooking, season both sides liberally with sea salt and coarsely ground black pepper. Press the seasoning into the meat so it adheres.

Sear and cook

Heat a heavy skillet (cast iron preferred) over high heat until smoking hot. Add 2 tbs neutral oil. When shimmering, add the steaks and sear without moving for 2.5–3 minutes to develop a deep crust. Flip and add 2 tbs unsalted butter, smashed garlic, and thyme. Tilt the pan and spoon the butter over the steaks (basting) for another 2.5–3 minutes for medium-rare (internal 54–57°C / 130–135°F). Adjust time ±1–2 minutes per side for desired doneness.

Rest steaks

Remove steaks to a warm plate, tent loosely with foil and rest for 6–8 minutes to allow juices to redistribute. Reserve pan juices for sauce if desired.

Peppercorn sauce

Prepare peppercorns

Coarsely crush the peppercorns with a mortar and pestle or in a zip-top bag with a rolling pin so there are some coarse pieces and some finer bits for flavor.

Sweat shallot

Using the same skillet (wipe out if excessively charred, leaving browned fond), add 1 tsp olive oil over medium heat. Add the minced shallot and sweat for 2–3 minutes until translucent but not browned.

Flambé with brandy (optional)

Carefully add 50 ml brandy or cognac. If comfortable and safe, tilt the pan to ignite briefly to burn off alcohol, or simmer for 1 minute to reduce heat and evaporate alcohol.

Reduce stock

Add 200 ml beef stock and the crushed peppercorns. Bring to a simmer and reduce by roughly half (4–6 minutes) until slightly syrupy and flavors concentrated.

Finish sauce

Lower heat and stir in 120 ml double cream and 1 tsp Dijon mustard. Simmer gently 2–3 minutes until sauce thickens slightly. Whisk in cold cubed butter (25 g) piece by piece to emulsify and give a glossy finish. Taste and season with up to 1 tsp salt as needed. Keep warm until plating.

Fries

Par-cook potatoes (first fry)

Rinse cut potatoes under cold water until water runs clear to remove excess starch, then dry thoroughly on clean kitchen towels. Heat vegetable oil to 150°C (300°F). Fry potatoes in batches for 5–6 minutes until soft but not colored. Remove and drain on paper towels.

Crisp fries (second fry)

Increase oil temperature to 190–195°C (375–385°F). Fry the par-cooked fries in batches for 2–3 minutes until golden and crisp. Drain on paper towels and season immediately with 1 tsp sea salt. Keep warm in a low oven (120°C / 250°F) on a tray while finishing other components.

Crispy onion rings

Make batter

In a bowl whisk together 120 g plain flour, 30 g cornstarch, 1 tsp baking powder and 1 tsp salt. Add beaten egg and 200 ml cold sparkling water, whisking lightly until just combined — a few lumps are fine. Keep batter cold.

Fry onion rings

Heat oil to 180°C (350°F) in a deep pot or fryer. Separate onion into rings, dredge lightly in a little flour (helps batter stick), then dip into the cold batter, shaking off excess. Fry in batches 2–3 minutes until golden brown and crisp. Drain on paper towels and season with a pinch of extra sea salt.

Garnish & plating

Plate steak and sides

Place a rested steak on each plate. Spoon 2–3 tbs of peppercorn sauce over or alongside the steak. Arrange a portion of fries and 3–4 crispy onion rings per plate.

Finish and serve

Add a small mound of watercress to each plate and a lemon wedge if desired. Serve immediately while steak is warm and fries and rings are crisp.