These super-crispy and browned air-fryer brussels sprouts with sweet onions and salty bacon--all amped up with bright lemon juice--are sure to be a hit, whether you serve them for a weeknight side dish or as part of your holiday spread for thanksgiving. This recipe makes enough to serve eight but is easily halved, though once you taste it you may well want a double serving. And if you prefer a vegetarian side, simply omit the bacon.