Wash Brussels sprouts and nip off the end of the stem and pull off any loose leaves.
Place sprouts into a large bowl. Drizzle with olive oil and sprinkle with salt and pepper.
Place a sheet of parchment paper on a baking sheet and place the Brussel sprouts on the parchment paper.
Bake for 20 to 25 minutes. The Brussel sprouts will be lightly browned on the outside and tender on the inside when they are done.
About 10 minutes before the Brussels sprouts are done, place the butter into a small pot over medium heat.
Swirl continually over the heat. The butter will begin to brown.
When the butter has become fragrant and has a caramel color, remove it from the pot, and slowly pour it into a heatproof dish. Be sure to leave as many solids as you can in the pot. Discard the solids.
Remove the Brussels sprouts from the baking sheet and place them on a plate to serve.
Drizzle the browned butter over the Brussel sprouts just before serving.