- 1/4 cup balsamic vinegar, (60ml)
- 2 teaspoons dijon mustard, (10ml)
- 1 teaspoon mayonnaise, (4g) optional
- 1/2 teaspoon kosher salt, (2g)
- 1/4 teaspoon black pepper
- 1/2 cup extra-virgin olive oil, (120ml)
- 1 pound flank steak, (454g), or flat iron steak
- Kosher salt, for seasoning
- Black pepper, for seasoning
- 2 tablespoon olive oil, (30ml)
- 4 cups arugula, (75g, 2 ½ ounces), 1-inch pieces
- 4 cups romaine lettuce, (140g, 5 ounces)
- 2 cups radicchio, (60g, 2 ounces), 1-inch pieces
- 1 cup cherry tomatoes, (160g, 2 ½ ounces), cut in half
- ½ cup thinly sliced cucumber, (72g, 2 ½ ounces)
- ¼ cup thinly sliced radish, (32g, 1 ounce)
- ¼ cup diced red onion, (38g, 1 ¼ ounce)
- 1 medium avocado, sliced or diced
- ¼ cup feta cheese, (40g, ¼ ounce)
In a medium bowl whisk together vinegar, mustard, mayonnaise, salt, and pepper.
Slowly drizzle in the olive oil and whisk until it becomes a thickened emulsified dressing.
Dry the surface of the steak with paper towels.
Season both sides of the steak with salt and pepper.
Heat a large cast-iron skillet over high heat until hot. Add the oil, once the oil is hot add the steak. Pressing down into the pan. Cook until the surface is browned, 4 minutes.
Flip the steak and cook until it reaches an internal temperature of 120 to 125°F (49 to 52ºC) for medium-rare, about 3 to 5 minutes.
Transfer the steak to a cutting board and rest for 10 minutes. Slice the steak against the grain into ¼-inch thick pieces. Cut smaller if desired.
In a large serving bowl mix together the arugula, romaine, and radicchio.
Top salad with tomatoes, cucumber, radish, onion, steak, avocado, and feta cheese.
Serve steak salad with balsamic vinaigrette.
When to stop cooking the steak
Target medium-rare doneness, taking the meat off once it hits an internal temperature of 120 to 125°F (49 to 52ºC). This may seem early, but the 10 minutes of rest will allow for carryover cooking to occur. The meat should reach about 130ºF (54ºC). Overcooking the steak will result in tough and chewy pieces.