Prep the Steak: First, cut your sirloin steak into cubes that are about 1-inch in size. Try to make them all about the same size so they cook evenly. Pat them dry with a paper towel.
Season the Steak: In a medium bowl, add the steak pieces. Drizzle the olive oil and Worcestershire sauce over the top. Then, sprinkle on the garlic powder, onion powder, oregano, salt, and pepper. Use your hands or a spoon to toss everything together until the steak is coated well.
Preheat the Air Fryer: Turn your air fryer on and set it to 400°F (200°C). Let it preheat for about 3-5 minutes.
Cook the Steak Bites: Place the seasoned steak bites in the air fryer basket in a single layer. Make sure not to overcrowd the basket; you might need to cook in two batches if you have a lot.
Air Fry: Cook for 6-8 minutes, shaking the basket halfway through cooking. For a medium-rare steak, 6 minutes is usually perfect. If you like it more well-done, cook for a couple more minutes.
Add Butter and Parsley: Once done, carefully take the steak bites out of the air fryer and put them in a clean bowl. Add the melted butter and fresh parsley and toss to coat. Let them rest for a minute or two before serving. This makes them extra juicy!