We Recreated London’s Most Famous Steak & Sauce

Ingredients

• 500 g Potatoes (Russet or Yukon Gold, skin left on for extra texture)
• 500 ml Vegetable Oil (Neutral oil for deep‑frying (canola, sunflower))
• 500 g Steak (Ribeye or Sirloin) (Trimmed, about 1‑inch thick, room temperature before cooking)
• 100 g Unsalted Butter (Divided into two 50 g portions, softened)
• 2 Shallots (Finely minced)
• 2 tbsp Fresh Parsley (Chopped)
• 1 tbsp Fresh Basil (Chopped)
• 1 tsp Fresh Tarragon (Finely chopped)
• 1 pinch Fresh Nutmeg (Freshly grated)
• 1 tbsp Lemon Juice (Juice of half a lemon)
• 1 tbsp Capers (Rinsed, keep the brine for adjusting sauce consistency)
• 2 tbsp Walnuts (Roughly chopped)
• 1 Egg Yolk (Large, at room temperature)
• 1 tsp Dijon Mustard
• to taste Salt
• to taste Black Pepper

Instructions

1. Prepare the Potatoes

   Wash the potatoes, leave the skins on, then slice them on a mandoline to an 8 mm thickness. Rinse the slices in a bowl of cold water for 5 minutes to remove excess starch, then drain and pat dry.

   Time: PT10M

2. Heat Oil for Frying

   Fill a deep‑fry pot with vegetable oil, about 3 inches deep. Heat to 170 °C (340 °F) using a thermometer.

   Time: PT5M

   Temperature: 170°C

3. Fry the Chips

   Working in batches, add the potato slices to the hot oil. Fry for 5‑6 minutes, or until golden‑brown and crisp. Remove with a slotted spoon, drain on paper towels, and keep warm.

   Time: PT6M

   Temperature: 170°C

4. Make the Herb Butter Base

   In a heavy‑bottom skillet over low heat, melt 50 g of butter. Add the minced shallots and sauté until translucent, about 3 minutes.

   Time: PT3M

5. Add Fresh Herbs and Aromatics

   Stir in the chopped parsley, basil, tarragon, and a pinch of freshly grated nutmeg. Cook for 1 minute, just until the herbs release their colour and aroma.

   Time: PT1M

6. Combine Capers, Walnuts, and Lemon

   Add the rinsed capers (with a splash of their brine), chopped walnuts, and lemon juice to the skillet. Stir briefly, then remove from heat.

   Time: PT2M

7. Prepare the Emulsion Base

   In a separate bowl, whisk together the egg yolk, Dijon mustard, and a pinch of salt until smooth.

   Time: PT2M

8. Emulsify the Sauce

   Slowly drizzle the warm butter‑herb mixture into the egg‑yolk mixture while whisking constantly. Once incorporated, whisk in the remaining 50 g of butter in small pieces until the sauce is smooth and glossy.

   Time: PT5M

9. Split and Re‑heat the Sauce

   Divide the sauce: keep 1/3 in a small pan, heat gently until just warm, then combine with the remaining 2/3. This restores a silky consistency after the initial cooling.

   Time: PT5M

10. Season and Sear the Steak

    Pat the steak dry, season generously with salt and pepper. Heat a clean skillet over high heat, add a thin drizzle of oil, then place the steak in the pan. Sear 40‑50 seconds per side for a medium‑rare crust, then flip and sear the edges briefly.

    Time: PT7M

11. Rest the Steak

    Transfer the steak to a plate, loosely cover with foil, and let rest for 5 minutes. This allows juices to redistribute.

    Time: PT5M

12. Plate and Serve

    Slice the rested steak against the grain, arrange the hot chips beside it, and drizzle generously with the green herb sauce. Serve immediately.

    Time: PT2M

Nutrition Facts

Calories

750

Protein

35 g

Carbohydrates

60 g

Fat

45 g

Fiber

5 g

Ingredient Substitutions

• Instead of Potatoes: Sweet potatoes
• Instead of Vegetable Oil: Peanut oil, Sunflower oil
• Instead of Steak (Ribeye or Sirloin): New York strip, Filet mignon
• Instead of Unsalted Butter: Clarified butter, Ghee
• Instead of Shallots: Red onion (finely diced)
• Instead of Fresh Parsley: Flat‑leaf parsley
• Instead of Fresh Basil: Thai basil
• Instead of Fresh Tarragon: Dried tarragon (¼ tsp)
• Instead of Fresh Nutmeg: Ground nutmeg (¼ tsp)
• Instead of Lemon Juice: White wine vinegar (½ tsp)
• Instead of Capers: Green olives (chopped)
• Instead of Walnuts: Pine nuts, Almonds
• Instead of Egg Yolk: Pasteurized egg yolk
• Instead of Dijon Mustard: Whole‑grain mustard
• Instead of Salt: Sea salt
• Instead of Black Pepper: White pepper

Equipment Needed

• Cutting Board
• Chef's Knife
• Mandoline or Chip Cutter
• Large Bowl
• Whisk
• Heavy‑Bottom Skillet
• Deep Fry Pot or Dutch Oven
• Thermometer
• Spatula
• Tongs
• Plate for Resting Steak

Critical Steps — Do Not Skip

• Cut potatoes to a uniform 8 mm thickness for even frying.
• Emulsify the butter‑herb mixture into the egg yolk without overheating.
• Sear the steak quickly on a smoking hot pan to develop a crust without overcooking.

Chef Tips from the Video

• Use a mandoline for perfectly even chips; the 8 mm setting mimics the restaurant’s texture.
• Reserve a tablespoon of the caper brine; it’s the secret to the sauce’s silky mouthfeel.
• For extra nuttiness, toast the walnuts lightly before adding them to the sauce.

Troubleshooting

Storage

Refrigerator: Sauce will keep 2‑3 days in an airtight container; re‑heat gently. Steak and chips are best served fresh.

Freezer: Do not freeze the sauce (emulsion may break). Cooked steak can be frozen for up to 2 months, sliced and reheated.

Room temperature: Do not leave the sauce at room temperature for more than 2 hours due to raw egg yolk.

Make-Ahead Tips

• The green herb sauce can be prepared up to 24 hours ahead; store chilled and gently re‑whisk before serving.
• Chop herbs and measure all sauce ingredients before starting to streamline the process.

Frequently Asked Questions