Preheat the air fryer to 400°F (205°C) for 5 minutes. A hot basket helps the steak build a crust.
Pat steaks dry with paper towels.
Dry surfaces sear better and brown more deeply.
Season the steaks generously on both sides with salt and pepper. Drizzle lightly with olive oil and rub to coat.
Toss the mushrooms with 1 tablespoon olive oil, a pinch of salt and pepper, and half the minced garlic. If you like, add a splash of Worcestershire or balsamic for extra depth.
Arrange in the basket: Place the steaks in the basket with space between them.
Scatter mushrooms around the sides, not on top of the meat.
Air fry the first side for 6–7 minutes for medium-rare, depending on thickness. Thicker cuts may need an extra minute.
Flip and add butter and herbs: Turn the steaks. Dot each steak with a small pat of butter.
Add remaining garlic and herb sprigs over the mushrooms and around the steaks.
Finish cooking for another 4–6 minutes, or until your target internal temp: 120–125°F (rare), 130–135°F (medium-rare), 140–145°F (medium). Use an instant-read thermometer for accuracy.
Rest the steak on a plate for 5–7 minutes. Tent loosely with foil.
This helps juices redistribute.
Toss mushrooms in the buttery juices left in the basket, then plate with the steak. Spoon any resting juices over the top. Finish with fresh herbs if you like.