Preheat oven to 450°F (240°C).
In a medium bowl, combine Brussels sprouts, olive oil, water, salt, and pepper. Toss until combined then transfer to a rimmed baking sheet. All cut sided should be facing down.
Cover sheet tightly with aluminum foil and transfer to the oven. Roast for 10 minutes then remove foil and cook for 12-15 more minutes, until the sprouts are tender and browned.
In the meantime, cook the bacon in a large skillet over medium heat until crisp. Transfer bacon to a paper towel-lined plate, then finely chop it. Leave the bacon drippings in the skillet.
When the Brussels sprouts are are tender transfer them to the skillet with the bacon drippings. Add chopped bacon, apple cider, fresh thyme, and toss until combined. Season with salt and pepper to taste and serve.