In a bowl, mix together the steak cubes and mushrooms, ensuring they are evenly sized for consistent cooking. Coat with melted butter, then season with Worcestershire sauce, garlic powder, salt, and black pepper.

Preheat the Air Fryer to 400°F for 4 minutes to ensure a good sear on the steak.

Place the seasoned steak and mushrooms into the air fryer basket or on the rack, spreading them out in a single layer. Air fry at 400°F for 10-18 minutes, shaking and flipping the ingredients about 3 times during the cooking process. The exact time may vary depending on the steak's thickness and desired doneness.

Check the steak's doneness and adjust the cooking time if you prefer it more well-done by adding 2-5 extra minutes.

(Optional) Garnish with minced parsley and drizzle with optional melted butter and/or chili flakes. Season with additional salt and pepper if desired. Serve warm.