Cube your sirloin steak. Toss with salt and pepper.
In a large skillet over medium heat add your olive oil. Place your cubed steak in the pan in a single layer.
Depending on how well done you like your steak, cook for a few minutes. Flip over.
Cook for a few more minutes, amount of time depends on how well done you want them cooked. Remove from heat to a plate or bowl.
Add your butter. When it is melted, add you garlic.
Cook for a minute or two. If you cook the garlic too long, it will go from brown to burnt really fast.
Add your steak back to the skillet. Sprinkle the parsley over the steak.
Serve warm with desired sides.