In a large resealable bag, combine Dijon mustard, minced garlic, onion powder, soy sauce, olive oil, and balsamic vinegar to create a flavorful marinade. Pat the flank steak dry, then season it generously with salt and pepper before placing it in the bag. Seal the bag, ensuring the steak is well-coated, and refrigerate for at least 2 hours, or ideally overnight, to enhance the flavors and tenderness.

When ready to grill, preheat your grill to high heat—about 450°F. This temperature is essential for achieving that beautiful char on the Balsamic Flank Steak. While the grill heats up, remove the steak from the marinade, allowing any excess to drip off. Reserve the marinade for glaze later.

Once the grill reaches the desired temperature, place the flank steak on the grates and grill for 3-5 minutes on each side. Cook until the steak reaches a medium-rare internal temperature of about 135°F, checking for a nice char on the outside.

While the steak is cooking, brush sliced zucchini with olive oil and sprinkle with salt. When the steak is halfway done, add the zucchini directly to the grill. Grill for about 2-3 minutes on each side until they are tender and have lovely grill marks.

Take the reserved marinade from the steak and pour it into a small saucepan. Bring it to a boil over medium heat until it reaches 165°F, ensuring food safety. Then, allow it to simmer for 2-3 minutes, stirring frequently until it thickens slightly.

In a mixing bowl, combine feta cheese with heavy cream. Use a hand mixer to blend until it reaches a smooth, creamy consistency.

Once the steak has finished grilling, let it rest for about 5 minutes to retain its juices, then slice against the grain for maximum tenderness. On each plate, spread a generous dollop of whipped feta, layer with the sliced steak and grilled zucchini, then drizzle the balsamic glaze over everything.