Preheat oven to 400°; slice baguette in half lengthwise, then divide + spread slices with butter + a sprinkle of salt; wrap baguette in foil + bake 7-10 min until warm + golden; slice in half + layer with a few slices of fresh mozzarella, return to the foil-lined sheet tray + bake uncovered 1-2 min til melty

Heat 1 tbsp oil in a large skillet over high; add ½ beef in a single layer + sear 1 min, push steak to the side + repeat the process; sauté 1-2 min constantly stirring until hot, season with salt/pep + fave seasonings

Divide steak to sandwiches + serve while hot