Step 1: Prepare the Balsamic Vinaigrette: In a small bowl, whisk together the balsamic vinegar, extra virgin olive oil, Dijon mustard, minced garlic, honey (if using), salt, and pepper until well combined and emulsified. Set aside.
Step 2: Prepare the Steak: Pat the flank or sirloin steak thoroughly dry with paper towels. Season generously on both sides with salt and freshly ground black pepper.
Step 3: Sear the Steak: Heat 1 tablespoon of olive oil in a cast-iron skillet or heavy-bottomed pan over medium-high heat until hot and shimmering. Carefully place the seasoned steak in the hot pan. Sear for 3-4 minutes per side for medium-rare, or adjust cooking time to your desired doneness. For medium-rare, the internal temperature should be around 130-135°F (54-57°C).
Step 4: Rest and Slice the Steak: Transfer the seared steak to a cutting board. Loosely tent with foil and let it rest for at least 5-10 minutes. This is crucial for juicy, tender steak. After resting, slice the steak thinly against the grain.
Step 5: Assemble the Salad: In a large bowl, combine the mixed greens, halved cherry tomatoes, sliced cucumber, and thinly sliced red onion. Drizzle with about half of the prepared balsamic vinaigrette and toss gently to coat the vegetables.
Step 6: Plate and Serve: Divide the dressed greens among two serving plates. Arrange the thinly sliced steak over the greens. Sprinkle with crumbled feta cheese and toasted walnuts. Drizzle with a little more balsamic vinaigrette, if desired. Serve immediately and enjoy your delicious steak salad recipe!