Combine the halved Brussels sprouts, olive oil, salt, pepper, red pepper flakes and parmesan cheese in a large bowl and toss to combine.
Place in air fryer basket and cook at 400 degrees F*(see notes). for 12 minutes, shaking the basket half way through. Cook until crisp on the outside and tender on the inside. Enjoy!
*No need to preheat the air fryer for this recipe, however, if the air fryer is already hot/preheated, you'll want to reduce cook time to 8 to 10 minutes, depending on size of Brussels sprouts. OVEN INSTRUCTIONS - Prepare recipe as indicated above, but spread out on foil lined baking sheet. Bake in preheated, 425 degrees F oven, for 15 to 20 minutes, stirring halfway through.