01 -
Remove the steak from refrigeration 1 hour before cooking to allow it to reach room temperature. Generously season all sides with salt and freshly ground black pepper.
02 -
Heat a large non-stick pan over medium-high heat and add a drizzle of oil or pork lard. Place the steak fat side down for 1 minute to render fat. Sear each side for 2–3 minutes, or until desired doneness. For enhanced flavor, add butter during the final minute and baste the steak with the melted butter.
03 -
Transfer the steak to a plate and let rest for 5 minutes. Slice the steak thinly across the grain.
04 -
In the same pan, add the sliced onions and season with 1 teaspoon salt. Cook over medium heat, stirring occasionally, for 10–15 minutes until onions are caramelized and softened. Drizzle 1 teaspoon balsamic glaze and cook until deeply golden. Set aside.
05 -
Toast both ciabatta halves until golden and crisp, either in a toaster or a pan over medium heat.
06 -
Spread lemon herb aioli on both toasted ciabatta halves. Arrange a layer of arugula, followed by sliced steak (with a pinch of salt if desired), caramelized onions, and finish with a drizzle of remaining balsamic glaze.
07 -
Slice the sandwich in half and serve warm.