Allow the steak to rest at room temperature for one hour. Preheat oven to 350 degrees Fahrenheit. Place chopped walnuts on baking sheet and toast. Remove from oven, and place into a medium sized bowl. Grate garlic over walnuts while still hot, and mix. Add cornichons, capers, mustard, thyme, sugar, vinegar, and salt and pepper. Set aside.

Place a cast iron skillet over medium-high heat. Generously coat the steak on both sides with Aleppo, kosher salt & cracked pepper. Drizzle sides with a high temp oil, such as peanut or vegetable. Place steak in hot pan and allow to sear each side for 2½ minutes or thermometer inserted reads 130 (for medium-rare). Remove steak from heat and place on cutting board to rest for 15-20 minutes.

Wipe the skillet and add scallions. Allow to char, about 4-6 minutes. Add to vinaigrette and mix. Slice steak on the bias and spoon vinaigrette over the top. Sprinkle with Aleppo & flaky sea salt.