Heat a skillet over medium high heat. Once the skillet is hot, add the bacon. Move it around the pan every 30 seconds-minute or so, until the bacon is fully cooked and crispy, and as much fat is rendered as possible.
Keep the fat in the pan and remove the bacon. Place it on a plate.
Add the Brussels sprouts to the pan with the bacon fat, with the largest flat sides of the sprouts facing the hot pan surface. Make sure the pan is not over crowded and that each sprout is touching the hot surface, which will ensure even browning.
After 1-2 minutes, season the sprouts with a generous pinch of salt and pepper, then toss the Brussels sprouts. Let them cook for another minute, then toss again. Continue doing so until they are adequately golden brown (probably another 3-5 minutes.)
Once the sprouts are charred to your liking, pour 1/4 cup of beer into the pan. Toss the sprouts around and scrape any golden brown bits off of the bottom. Adjust the heat to high and let the beer cook off.
While the beer is cooking off, mix the dijon mustard and honey in a small bowl until combined.
Once there is no more liquid left in the pan of Brussels sprouts, adjust the heat to medium low. Add the bacon back and pour all of the honey mustard mixture onto the Brussels sprouts and bacon. Toss until they are fully coated and remove the pan from the heat.
Plate and serve immediately! Enjoy!