Preheat grill to medium high heat. Sprinkle chicken breasts with salt and pepper and grill 4-5 minutes per side, or until cooked through. Remove from grill and set aside. Slice into strips after it rests for a few minutes.

While chicken cooks, melt the butter in a sauce pan and add the onions. Cook until caramelized, about 10-15 minutes. Stir frequently.

Once onions and chicken are done, assemble the flatbreads. Spread the bbq sauce first, top with chicken slices, and then the cheese.

Put on the grill and grill until cheese is melted, about 5 minutes.

Once grilled, remove from the grill and top with the arugula and red cabbage. Drizzle with ranch dressing. Cut into strips and serve immediately.