Prep the beef: Pat the cubes very dry with paper towels. Dry surfaces brown better and won’t steam in the air fryer.
Season: In a large bowl, toss beef with oil, salt, pepper, garlic powder, onion powder, smoked paprika, and thyme.
If using, add soy sauce or Worcestershire. Coat evenly.
Preheat: Heat the air fryer to 400°F (200°C) for 3–5 minutes. A hot basket helps with searing.
Arrange: Spread beef cubes in a single layer in the basket. Do not overcrowd. Work in batches if needed so the hot air can circulate.
Cook: Air fry at 400°F for 6–9 minutes, shaking the basket or flipping cubes halfway.
Time varies by cube size and your air fryer model.
Check doneness: For medium-rare, aim for an internal temp of 130–135°F; medium is 140–145°F. Pull them a few degrees early—they’ll rise slightly as they rest.
Finish (optional): Toss the hot cubes with a small pat of butter and parsley for a glossy, steakhouse finish.
Rest and serve: Let the beef rest 3 minutes, then serve with your favorite sides or sauces.