In a large skillet over medium-low heat, cook the bacon until crispy, set aside, and leave the drippings in the pan.
While the bacon is cooking, trim off the stems of the brussel sprouts and cut them in half lengthwise.
Add the brussel sprouts, garlic, thyme (if using), salt, and pepper to the pan.
Sear the brussel sprouts, allowing them to sit in the pan and tossing every minute or so until slightly charred over medium-low heat, about 8-10 minutes.
Add the stock to the pan, scrape any brown bits off the bottom of the pan.
Cover and reduce the heat to low, and cook for 5 minutes until tender-crisp.
Uncover and allow any excess liquid to cook-off.
Finish with the butter, taste, and adjust seasoning, if needed.
Chop the bacon and add it to the pan, stir to mix in and serve.
Notes
When shopping for brussel sprouts, you want them to be bright green and wrapped really tight. Remove any loose leaves before cooking.