01 - Whisk together balsamic vinegar, olive oil, minced garlic, Dijon mustard, salt, and pepper in a small bowl. Place the steak in a zip-top bag or shallow dish, pour the marinade over, and refrigerate for at least 20 minutes or up to 2 hours for deeper flavor.
02 - While the steak marinates, brush the corn ears with olive oil and heat a grill or grill pan to medium-high. Grill the corn for 8 to 10 minutes, turning occasionally, until lightly charred on all sides. Let cool, then cut the kernels off the cob.
03 - Remove the steak from the marinade and grill to desired doneness, about 3 to 4 minutes per side for medium-rare. Transfer to a cutting board and let rest for 5 minutes, then thinly slice across the grain.
04 - Arrange the mixed salad greens on a large serving platter or in a wide bowl. Scatter the grilled corn kernels, halved cherry tomatoes, sliced red onion, avocado slices, and crumbled Gorgonzola over the greens.
05 - Whisk together balsamic vinegar, extra-virgin olive oil, honey, Dijon mustard, salt, and black pepper in a small bowl until fully emulsified.
06 - Drizzle the vinaigrette evenly over the assembled salad, arrange the sliced steak on top, and serve immediately.