The amount of everything in this recipe depends on how many Brussels sprouts that you want to eat.
Preheat your oven to 400 degrees F (205 C).
Trim the tough stems off of your Brussels sprouts, cut each one in half or quarters depending on size. Add the trimmed and cut sprouts to a large bowl.
Add olive oil, salt, and pepper to the bowl with the sprouts and toss to combine everything.
Place each Brussels sprout on a baking sheet, cut side down.
Bake at 400 degrees F for 18-20 minutes. There should be some browning, some of the loose leaves should appear to have burned, but they will still be ok. The main thing to check for is the tenderness of the sprouts themselves. Poke with a fork to ensure they are soft but still have some texture.
Remove the roasted sprouts to a bowl and top with a few teaspoons of balsamic reduction (if using). The reduction adds sweetness that will help balance some of the Brussels sprout bitterness.
Serve and enjoy.