Chop the bacon into small pieces and cook in a skillet over medium heat, stirring occasionally, until crispy and browned (about 8-10 minutes). Transfer to a paper towel to drain and cool. While the bacon cooks, trim the brussels sprouts by removing any yellowed or damaged outer leaves, then cut each sprout in half lengthwise, keeping the stem end intact so the layers hold together during cooking. In a small bowl, whisk together the pepper jelly, cayenne pepper, and red pepper flakes to create a smooth, combined glaze that's ready to coat the sprouts.

Bring a large pot of water to a rolling boil and add the kosher salt. The salted water seasons the sprouts from the inside out. Carefully add the halved brussels sprouts to the boiling water and cook for exactly 5 minutes—this partial cooking softens the inside while keeping them firm enough to crisp in the air fryer. Drain the sprouts in a colander and rinse under cold running water for about 3 minutes to stop the cooking process and remove any excess starch.

Pat the cooled brussels sprouts completely dry using a clean kitchen towel or paper towels—moisture prevents proper crisping. I find that really drying them makes a huge difference in achieving that golden, caramelized exterior. Arrange the sprouts cut-side down in the air fryer basket in a single layer and cook at 400°F for 4 minutes. Shake the basket or flip each sprout over and cook for another 4 minutes until the cut sides are deeply browned and caramelized.

Transfer the hot, crispy brussels sprouts to a large mixing bowl. Pour the pepper jelly mixture from Step 1 over the warm sprouts and toss gently but thoroughly to coat every piece with the sweet and spicy glaze. The residual heat from the sprouts will warm the jelly and help it adhere to the crispy surface. Add the cooled bacon pieces and toss once more to distribute evenly throughout. Serve immediately while the sprouts are still warm and the glaze is slightly tacky.