Equipment
Ingredients
Steak
- 500 g sirloin steak, room temperature
- 15 ml neutral cooking oil
- 30 g unsalted butter
- 5 g fresh thyme, whole sprigs
- 2 garlic, crushed
Potatoes
- 600 g floury potatoes, peeled and roughly chopped
- 45 ml olive oil
- 4 garlic, smashed in skins
- flaky sea salt
Cavolo Nero Dressing
- 100 g cavolo nero, stems removed and discarded, leaves roughly chopped
- 80 ml extra virgin olive oil
- 30 ml lemon juice, freshly squeezed
- 15 g capers, drained
- 10 g dijon mustard
- 1 garlic, grated
Nutrition (per serving)
Method
Preheat your oven to 220°C/430°F and place a large roasting tray inside to heat up.
Place the chopped potatoes in a large pot of cold, heavily salted water. Bring to a boil and simmer until the edges yield slightly to a knife.
Drain the potatoes into a colander. Shake the colander vigorously to roughen the edges of the potatoes, then let them sit undisturbed to steam dry completely.
Carefully remove the hot tray from the oven. Add the olive oil, smashed garlic, and steamed potatoes. Toss to coat evenly, space them out, and roast until golden and crispy.
While the potatoes roast, bring a pot of heavily salted water to a rolling boil. Drop in the cavolo nero leaves and blanch until tender and bright green.
Using a slotted spoon, immediately transfer the blanched cavolo nero to a bowl of ice water to stop the cooking process and lock in the color. Drain and squeeze out as much water as physically possible.
Place the squeezed cavolo nero, extra virgin olive oil, lemon juice, capers, Dijon mustard, and grated garlic into a food processor. Blend until it forms a slightly coarse, vibrant green dressing. Season with salt to taste.
Pat the sirloin steaks completely dry with paper towels and season generously with flaky sea salt. Heat a cast iron skillet over high heat until smoking, add the neutral oil, and lay the steaks in the pan.
Flip the steaks, then immediately add the butter, crushed garlic, and thyme to the pan. Continually spoon the foaming, aromatic butter over the steaks as they finish cooking to an internal temperature of 54°C/130°F for medium-rare.
Transfer the steaks to a warm plate and pour the pan juices over them. Let them rest undisturbed so the muscle fibers relax and retain their juices.
Slice the rested steak against the grain. Serve alongside the crispy roasted potatoes, and spoon the bright cavolo nero dressing generously over the meat and the plate.
Chef's Notes
- Drying the steak is paramount for a proper Maillard reaction; water is the enemy of a good crust because the energy will go into boiling the water rather than searing the meat.
- Basting the steak with foaming butter, garlic, and thyme is known as 'arroser'. This technique creates a rich, complex flavor profile on the exterior while cooking the meat more gently from the top down.
- The cavolo nero dressing acts as an acidic, slightly bitter counterbalance. The sharpness of the lemon and capers is essential to cut through the rich fat of the steak and the starch of the roasted potatoes.
- Choosing a floury potato like Maris Piper or Russet allows the parboiling process to break down the starchy exterior. When tossed with hot fat, this starchy slurry becomes the ultimate crispy shell.
Storage
Refrigerator: 3 days — Keep dressing in a separate airtight container with a layer of olive oil on top to prevent oxidation.
Reheating: Reheat steak gently in a warm oven or slice and eat cold. Re-crisp potatoes in a 200C oven for 10 minutes.
