Cut steak into 1″ cubes.
Heat olive oil in a sturdy pan over medium-high heat.
Meanwhile, pat the steak dry with a paper towel, then season liberally with salt and pepper.
Once the olive oil is hot, add the steak to the pan, making sure not to crowd the steak. Work in batches, if necessary. Cook for at least 2 minutes per side to allow it to brown. Continue cooking until desired doneness, then transfer to a bowl.
Wipe the pan clean with a paper towel, then return to heat. Add in butter, minced garlic, and red chile flakes. Saute until fragrant, 30 – 60 seconds.