before slicing into 1/4-inch thick slices.
whisk together all spices in a small bowl until combined. brush onions with oil on both sides. rub 1 side of each onion with some of the spice mixture and place rub side down on the grill. grill until golden brown and a crust has formed. turn the onions over and continue grilling until just cooked through. serve with the steaks. 