01 - In a shallow dish, whisk together balsamic vinegar, olive oil, minced garlic, Dijon mustard, kosher salt, and black pepper. Add steak and turn to coat evenly. Refrigerate and marinate for at least 15 minutes, or up to 2 hours.
02 - Preheat grill, grill pan, or skillet over medium-high heat. Remove steak from marinade and pat dry. Grill or sear steak for 3–4 minutes per side until medium-rare or preferred doneness.
03 - Transfer steak to a plate, cover loosely with foil, and let rest for 5 minutes. Slice steak thinly against the grain.
04 - In a small bowl, whisk together balsamic vinegar, Dijon mustard, honey, olive oil, and seasoning until emulsified.
05 - In a large mixing bowl, combine salad greens, cherry tomatoes, sliced red onion, crumbled Gorgonzola, toasted nuts, and cucumber.
06 - Drizzle half of the balsamic vinaigrette over salad ingredients and toss gently to coat.
07 - Distribute salad onto plates, top with sliced steak, and finish with remaining vinaigrette.