Preheat oven to 450°F or air fryer to 390°F
Toss frozen green beans with olive oil, salt, black pepper, garlic, onion powder, and red pepper flakes
For oven method: Roast at 450°F for 30 minutes, adding parmesan cheese halfway through and shaking the pan
For air fryer method: Cook at 390°F for 12 minutes, adding parmesan cheese in the last 5 minutes
