Preheat the oven to 350 degrees F.
Remove the outer layer of leaves from the sprouts. Cut off the stems and cut each sprout in half.
In a large cast iron skillet, add the bacon and cook over medium heat until about halfway done. Remove the bacon from the skillet and reserve the grease.
Melt the butter in the skillet with the bacon grease.
Place the brussel sprouts, cut-side down, in the skillet and cook over medium-low heat, for 3 to 4 minutes. Season with salt and pepper. Sprinkle the bacon evenly on top. Bake for about 20 to 25 minutes, or until fork tender.
Remove from the oven and sprinkle with the Parmesan and serve.