Add the bacon in a single layer to the air fryer basket. Cook at 400 degrees F for 10 minutes, turning halfway through, until the bacon is mostly cooked but still soft.

Meanwhile, cut the brussels sprouts in half lengthwise (quarters if they’re very large) and place them in a large bowl. Drizzle them with olive oil, tossing to coat. Sprinkle with salt and pepper.

When the timer is up, remove the bacon and chop it into small pieces. Add the bacon to the bowl with the brussels sprouts and toss.

Discard any excess grease from the air fryer, then add the contents of the bowl to the basket. Cook at 400 degrees F for 20-25 minutes, shaking the basket every 5-10 minutes to ensure they are evenly browned. 

Use a slotted spoon to transfer the brussels and bacon to a serving bowl, then drizzle with the desired amount of balsamic glaze, or serve it on the side.