Start by slicing the onions and the steak against the grain.

Rub the steak with olive oil, salt, pepper, and garlic powder.

Heat a skillet or grill pan over medium-high heat.

Add a tablespoon of olive oil to the skillet and toss in the sliced onions. Cook until caramelized, about 5-7 minutes.

Remove the onions and add the steak to the skillet. Cook for 4-5 minutes on each side.

Remove the steak from the pan and let it rest for 5 minutes.

After resting, slice the steak thinly against the grain.

Layer the sliced steak and caramelized onions on the sandwich rolls. Add any optional toppings.