Preheat a barbecue, indoor grill, or a skillet for stovetop cooking.
Combine the turkey, breadcrumbs, steak seasoning, ground cumin, egg whites, garlic, onions, and some salt and pepper in a large bowl. Mix thoroughly with your hands. (Be careful not to over-knead the mixture; otherwise the burgers will be tough.) Form the meat into patties about ¾-inch thick.
If using a grill, cook the burgers over high heat until the internal temperature reaches 170 degrees F. If using the stovetop, cook the burgers over medium-high heat until the internal temperature reaches 170 degrees F.