Preheat the air fryer. Set it to 400°F (200°C) for at least 3 minutes. A hot basket helps the veggies sear and crisp.

Prep the vegetables. Cut broccoli into evenly sized florets. Halve or quarter mushrooms so they’re similar in size to the florets. Pat everything dry with a clean towel to remove surface moisture.

Toss with seasoning. In a large bowl, combine broccoli and mushrooms with olive oil, garlic powder, onion powder, salt, and pepper. If using soy sauce, add it now for an umami boost. Mix until everything is well coated but not drenched.

Load the basket. Add the vegetables in a single layer if possible. A little overlap is fine, but avoid a deep pile. Work in batches if needed for best crispiness.

Air fry and shake. Cook at 400°F for 10 to 12 minutes. Shake the basket or toss with tongs halfway through to promote even browning. Start checking at the 8-minute mark—edges should be browned and the broccoli stem should be just tender when pierced.

Finish and serve. Taste and adjust salt. Add a squeeze of lemon, a pinch of chili flakes, or Parmesan if you like. Serve hot.