Alternatively, you can cook the steaks and onions, on the stovetop, in batches, in a lightly oiled large skillet or grill pan over medium-high heat. Sear the steaks until charred and caramelized at the edges; 2 to 3 minutes per side. Cook the onions and scallions next, until charred but still crunchy; 1 to 2 minutes per side. Discard any remaining marinade.