Fill a large container or pot with water. Attach the sous vide precision cooker and set the temperature to 183ºF/84ºC.
Wash and dry Brussels sprouts. Trim the ends and then slice the sprouts in halves lengthwise.
In a large bowl, mix the halved sprouts with 1 tablespoon olive oil, salt and pepper. Toss until they are evenly coated.
Add the Brussels sprouts into a zip-lock bag and arrange in a single layer. (Make sure to arrange in one layer. If your bag is not large enough, use multiple bags). Feel free to use a vacuum sealer if you have one.
Seal the bag using the “water displacement” technique or a vacuum sealer. (Just seal all but one corner of the bag. Slowly place it in the water bath, and make sure everything below the zip-line is covered by water. Then seal the rest of the bag.)
Keep the bag in the warm water bath and cook for 40 to 45 minutes. Make sure to submerge the Brussels sprouts completely. You can use heavy kitchen items such as saucepan and kitchen tongs to weight down the bag.
When the time goes off, take the bag out and remove Brussels sprouts from the bag. Pat dry with paper towels. (Wet surface will interfere with searing).
In a large skillet over medium-high heat, add the remaining 1 tablespoon olive oil.
Add Brussels sprouts and fry for 3-4 minutes until browned, stirring occasionally. Remove from skillet and transfer to a plate.
Serve warmly, and drizzle with optional balsamic vinegar and sprinkle with shredded parmesan cheese.