Slice the beef into thin strips, about ¼ inch thick, cutting against the grain for a tender texture.
In a large bowl, combine the soy sauce, Worcestershire sauce, brown sugar, garlic powder, onion powder, black pepper, and red pepper flakes. Stir until the sugar is mostly dissolved.
Add the beef strips to the marinade, making sure they’re well coated. Cover and refrigerate overnight or for at least 6 hours.
Preheat your air fryer to 180°F (82°C).
Arrange the marinated beef strips in a single layer in the air fryer basket, ensuring they don’t overlap.
Air fry for 2–3 hours, flipping the strips halfway through. The jerky is ready when it’s dry but still slightly pliable.
Let the jerky cool completely on a wire rack before transferring it to an airtight container for storage.
Variations:
Spicy Kick: Add 1 tsp of hot sauce or extra red pepper flakes to the marinade for more heat.
Smoky Flavor: Incorporate a few drops of liquid smoke to mimic traditional smoked jerky.
Sweet and Tangy: Mix in a tablespoon of apple cider vinegar and honey for a tangy-sweet twist.
Teriyaki Style: Substitute the Worcestershire sauce with teriyaki sauce and add a dash of ginger powder.