Preheat the air fryer to 350°F. Bring a pot of water to a boil over high heat. Add the Brussels sprouts to the boiling water and cook until fork-tender, about 10 minutes. Drain well. Let cool for about 5 minutes while continuing to drain.
Place the slightly cooled Brussels sprouts on a flat plate or small sheet pan and use a glass or heavy measuring cup to press down and flatten each sprout until it splits open.
Lightly coat the basket of the air fryer with olive oil spray and spread the Brussels sprouts across the pan. Spray the smashed Brussels with olive oil and sprinkle with salt and pepper.
Air fry for 10 minutes, until the edges have browned and are beginning to crisp. Turn the sprouts over, and air fry for an additional 5 minutes until deeply browned and crisp.
Transfer the Brussels to a plate and drizzle with balsamic reduction or glaze before serving. These are also great served with Bang Bang Sauce.
Notes
Do not cut the Brussels in half or they will cook far too quickly and turn to mush. Leave the Brussels WHOLE to be smashed flat after boiling.Just a note about the cooking time for this recipe. Watch while they are boiling and pull them as soon as they are fork tender. If they are fully cooked and soft, they will be mush by the time you smash them.