Heat a grill pan over a high heat, brush oil onto the steaks and season them with salt and pepper. Grill briefly on both sides until they are evenly brown and feature a striped pattern. Leave the steaks to cool down briefly in a cold oven dish. Spread a thin layer of butter onto the bread. Divide the rocket over the 4 slices. Crumble the blue cheese and sprinkle over the rocket. Cut the steaks into thin slices and place on the cheese, covering with a last slice of bread. Slice through the stacked slices of bread and place on a plate. Dress the remaining rocket with a dressing and serve with the sandwich.
Fry the Ziggy Fries for 4 to 5 minutes at 175°C. Serve with the steak sandwich.