Combine the cubed steak with paprika, salt, black pepper, onion powder, and red chilli flakes in a bowl and mix thoroughly to coat all pieces.
Lightly coat the seasoned steak with low calorie cooking spray and toss again to ensure even coverage.
Heat your air fryer to 200°C (400°F) for five minutes before cooking.
Arrange the steak evenly on the air fryer grill plate and cook for six minutes, flipping halfway through.
Remove the steak from the air fryer and take out the grill plate, keeping the juices in the basket for the sauce.
Return the steak to the air fryer with garlic, melted butter, and chopped parsley, tossing to combine, then air fry for another 1-2 minutes.
Sprinkle extra parsley over the steak bites, adjust salt and pepper if needed, and serve immediately with your favorite sides.