Cut steak into small cubes. Season with salt and pepper.
Add oil to a large skillet (use a cast iron, trust me). Once the pan is hot, add the steak in batches so as not to overcrowd the pan.
Cook for 4-5 minutes, stirring to get an even sear. If cooking in batches, pull out the first round and sear the remaining steak.
Reduce the heat to low and melt butter. Add minced garlic and let it simmer for about a minute.
Add all the steak back to the pan. Turn off the heat and stir it around.
Remove and sprinkle with parsley.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.