Preheat the oven to 400 degrees. Place parchment paper or aluminum foil on a baking sheet.
Cut the ends off the Brussels sprouts, then cut them in half and quarters if they are large.
Place them in a large bowl and add the olive oil, half of the Parmesan cheese and salt and pepper and toss them.
Then place them on a baking sheet and roast for 20-25 minutes stirring about halfway.
Add the bacon and the rest of the Parmesan and additional salt and pepper if needed serve.
Video
Notes
Air fryer directions: Preheat air fryer to 375°F. Arrange Brussels sprouts in a single layer (work in batches if needed). Air fry for 12–15 minutes, shaking the basket halfway through, until tender and golden brown.