Add oil and potatoes. Let potatoes cook undisturbed for 6 minutes, then flip, salt and cook for an additional 6 minutes.
While the potatoes are going, slice the steak into 1" squares and season generously.
Slide the potatoes over to the side of the skillet, melt the butter in the skillet and spread around the empty half of the pan.
Add steak and cook for 1 minute, flip and cook each additional side for 1 minute.
Mix in potatoes and serve.
Notes
Keep an eye on the potatoes so they don't burn.Adjust cook time of the steak for your desired doness. 4 minutes total will cook the steak to about a medium