1. Take a large skillet and add olive oil to the bottom. 
2. Put the pan on medium heat.  
3. Add the garlic and chili pepper to the pan.  Allow the garlic to toast and chili pepper to heat up with the oil. This should take about 3 minutes.
4. In a single layer, add the frozen Brussels sprouts to the pan.  Season them with salt and pepper and allow them to cook for about 5 minutes.  During this time they will defrost and it will add some moisture to the pan.  
5. When the Brussels sprouts are completely defrosted and become soft, take a wooden spoon or sturdy spatula and press down on them.  Flatten them out as much as you can.  

By increasing the surface area that is touching the bottom of your pan you will be able to help them caramelize.  Let them cook for 3-5 minutes until they become golden brown.

1. Flip the Brussels sprouts and press down on them again.  Drizzle the balsamic vinegar all over the vegetables.  Let them cook for an additional 3-5 minutes
2. Transfer them to a plate and serve.  
3. Enjoy!