Preheat oven to 350F.
Arrange slices of bacon on a lipped baking sheet lined with parchment paper and bake for about 20 minutes in the oven until crispy. When done, remove bacon with tongs and set aside on a plate.
Peel and cube the beets.
Remove outer leaves of Brussels sprouts and quarter.
Mince the garlic.
Add in the beets, Brussels sprouts and garlic to the bacon fat and gently combine to coat veggies.
Sprinkle with dried thyme, salt, and pepper.
The veggies should be in a single layer - not touching the sided of the baking sheet. If necessary, prepare in batches.
Roast for about 45 minutes until everything has caramelized slightly.
Transfer beets and Brussels sprouts to a large bowl. Crumble the cooled bacon and add it to the veggies. Toss with balsamic vinegar to taste and serve.