Warm oil in a large skillet over medium heat. Add the garlic and Brussels sprouts. Try to get as many sprouts face-down on the pan as you can. Let them cook, undisturbed, for 8 minutes.
Add salt and pepper and stir the Brussels sprouts. Continue cooking until the brussels sprouts are tender, stirring occasionally.
Turn off heat and drizzle with balsamic vinegar, stir, and adjust seasoning, if needed.
TO STORE: Let the sprouts cool completely and store in an air-tight container in the fridge for 3-4 days.TO REHEAT: Warm sprouts on a skillet on medium heat. While you can microwave the Brussels sprouts, it can make them soggy.TO FREEZE: While I don't recommend freezing cooked Brussels sprouts since they will get soggy when reheated, you can store them in the freezer for up to 3 months. When ready to enjoy, use the instructions above to reheat.