While Air Fryer preheats, spray both sides of the steak and season both sides with the steak seasoning.
Spray the basket of the Air Fryer with avocado oil. Place the seasoned sirloin steak in the basket and cook for 10 minutes. Flip halfway through the cooking time.
Place a pat of butter on the steak and let it rest for 5 minutes. Once it's rested, slice and enjoy.
Notes
More than 1 steak - You can double, triple, quadruple this recipe. Just make sure you don't over crowd the Air Fryer basket. I have cooked up to 4 larger sirloin steaks in my 6-quart Air Fryer before with no issues.
Resting - Any time you cook steak you want to ensure that it has time to rest. This will help seal in the juices giving you optimal flavor. I recommend letting your steak sit for 5 minutes before slicing.
Slicing - Always slice beef against the grain. The "grain" is the pattern on the meat. If you slice it with the grain of the meat you risk having extra chewy meat.