Heat 1 tbsp oil in skillet over med; thinly slice onion + sauté 8-10 min until browned; season with salt + add 2 tbsp water; cover + cook 3-5 min until softened; set aside

Heat 1 tbsp oil in skillet over med-high; pat steak dry, season with salt/pep + sear 3-4 min per side for med-rare (for more well done add 1-2 min per side); for best results, use tongs to hold steak up on edges for 1 min to render fat crispy; rest 5 min + cut into ½-inch slices

Slice 2 buns in half; toast until warm + golden; spread buns with sauce then top with steak slices + onions—that looks so good!