You can also par-boil them first, drain and then continue with the air frying recipe method. Par boiling helps make them a little softer and more cooked through the center. Cooking times will vary depending on the size of brussels sprouts. We like our brussels sprouts brown, crispy and tender. For small to medium brussels sprouts, cut them in half. If they’re larger, then cut them into thirds. Most importantly, try to buy them in all the same size for consistent cooking. We used a 3.7 qt air fryer.