First, start by making the chimichurri. Remove the seeds from the chili pepper and finely chop.
Finely chop the parsley and mince the garlic cloves.
Next, add the chopped chili pepper, parsley and garlic to a bowl.
Add olive oil, red wine vinegar, salt, ground black pepper and dried oregano to the same bowl and mix well to combine.
Reserve 1/3 cup of the chimichurri to marinate the steak.
Chill the rest of the chimichurri in the refrigerator for at least 1 hour before serving.
Place the flank steak in a bowl or zip loc bag and add 1/3 cup of chimichurri to the steak making sure to coat it completely with the chimichurri. Marinate for at least 30 minutes or overnight.
Preheat the air fryer to 400 degrees F for 5 minutes.
Place the marinated flank steak in the preheated air fryer and cook at 400 degrees F for 12 minutes. This is for medium doneness. I’ve included tips in the notes below for other levels of doneness. You don’t have to flip the steak over.
Let the flank steak sit in the air fryer basket for 10 minutes before removing and serving.
Finally, serve the air fryer flank steak and top with more chimichurri if desired.