Take the New York Strip Steak out of the refrigerator and let it rest at room temperature for about 1 hour. Season both sides with salt and black pepper.

Heat a large skillet over medium-high heat. Add the seasoned steak to the pan, fat cap side down, and sear for about 2-3 minutes on each side until a golden crust forms.

Remove the steak from the skillet and let it rest for 5 minutes on a cutting board.

In the same skillet, add the sliced onions and sprinkle with a pinch of salt. Sauté over medium heat for about 10-15 minutes until golden brown, adding balsamic glaze in the last few minutes.

Slice the ciabatta loaf in half and toast cut-side down until golden brown.

Spread lemon herb aioli on both toasted halves, then layer with arugula, sliced steak, and caramelized onions. Drizzle additional balsamic glaze on top before closing the sandwich.

Cut the sandwich in half and serve warm.