Rub the flank steak with Larry the Cable Guy Steak Seasoning and properly coat and press in the seasoning. Let the steak marinate for at least 30 minutes, or overnight.
Heat olive oil in a skillet over medium heat. Add the sliced onions, sprinkle with sugar and a pinch of salt. Cook until the onions are golden brown and soft, about 15-20 minutes. Set aside.
Grill the steak on high heat for about 5-6 minutes per side or until it reaches your desired level of doneness. Remove from the grill. Slice against the grain after resting.
Spread the caramelized onions evenly over the flatbread. Arrange the sliced steak on top of the onions. Sprinkle blue cheese crumbles over the steak.
Preheat your oven to 400°F (200°C).
Place the assembled flatbread on a baking sheet and bake for about 10-12 minutes until the edges are crisp and the cheese is slightly melted.
Remove the flatbread from the oven and immediately top with fresh arugula and balsamic glaze if desired for an added touch of sweetness and acidity. Enjoy!
