Aillade is an emulsified sauce of nuts, garlic and oil. It’s not uncommon to find versions that call for almonds or pistachios, but we decided to use the traditional walnut. In this recipe we serve it over strip steak and fresh greens.
Aillade is undeniably rich, so to lift its flavor and make a delicious accompaniment to simple seared steak, we add lemon zest and juice, capers and a good amount of parsley. We also keep the texture rather coarse and thin the consistency with water.
1/2 cup walnuts, roughly chopped
2 tablespoons fresh oregano, roughly chopped
2 tablespoons drained capers, roughly chopped
1 medium garlic clove, smashed and peeled
2/3 cup lightly packed fresh flat-leaf parsley, roughly chopped
1/4 cup extra-virgin olive oil, plus more to serve
1 teaspoon grated lemon zest, plus 2 tablespoons lemon juice
Kosher salt and ground black pepper
2 1-pound beef strip steaks, each about 1 inch thick, trimmed and patted dry
1 tablespoon grapeseed or other neutral oil
In a food processor, combine the walnuts, oregano, capers and garlic. Set aside 2 tablespoons of parsley for serving, then add the remainder to the food processor. Process until finely ground, about 10 seconds. Add the olive oil, lemon zest and juice, 2 tablespoons water, and 1/4 teaspoon each salt and pepper, then pulse pulse well combined, 3 to 5 pulses. Transfer to a small bowl; set aside.
Season the steaks on both sides with salt and pepper. In a 12-inch skillet over medium-high, heat the neutral oil until barely smoking. Add the steaks, reduce to medium and cook until well browned on the bottoms, 5 to 7 minutes. Flip the steaks and cook until the second sides are well browned and the centers register 120°F for medium-rare, another 5 to 7 minutes. Transfer to a serving platter, tent with foil and lest rest for 10 minutes.
Transfer the steaks to a cutting board, cut them on the diagonal into ¼- to ½-inch-thick slices. Return to the platter and spoon on the sauce. Sprinkle with the reserved parsley and drizzle with additional olive oil.
Tip: Don’t put unchopped nuts and parsley into the food processor. A cursory chop before grinding ensures the sauce has a uniform texture. Also, don’t use extra-virgin olive oil to sear the steaks, as its smoke point is too low. Use grapeseed or other neutral oil to achieve the best browning and to avoid the off flavor of overheated olive oil.