Wipe the steak dry and put them in a dish or freezerbag.
Mix together the soy sauce, oil, garlic ketchup and oregano - pour this over the steaks. Season with ground pepper. Let them marinate for at least an hour, longer if you can.
Heat the BBQ, grill or griddle pan. Take the steaks out of the bag and sear them on each side for 30 second then keep turning them over until they are cooked through to your liking (the cooking time also depends on the thickness of the steak).
Let them rest for 5-10 minutes before serving.
You can slice them into 2cm strips if you wish - these you can add to various salads or make sandwiches, wraps with them.