Pre-heat the sous vide water bath to 140ºF.

Season the chicken breasts with salt and freshly ground black pepper. Place the chicken breasts in a zipper lock plastic bag along with the sprigs of fresh thyme. Remove as much of the air as possible from the bag using a vacuum pump or by submerging the bags one at a time in the water up to the zipper seal (don’t let any water into the bag), and allowing the water to displace the air in the bag. Seal the bag and drop it into the water bath.

Cook in the sous vide water bath for one hour, or as long as 2 hours.

While the chicken is cooking, combine the balsamic vinegar, mustard, honey, brown sugar and smashed garlic cloves in a small saucepan. Bring to a simmer over medium heat and simmer gently for 15 to 20 minutes, or until it thickens slightly. Set aside.

When the time is up, remove the chicken from the zipper lock bag and pat it dry with paper towels. Pre-heat a skillet over medium-high heat. Add the olive oil and butter and then sear the chicken breasts on both sides until nicely brown. Remove the chicken to a side plate and add the tomato to the skillet and toss around for a minute. Pour in the reduced glaze and simmer for a minute. Add the thyme and then return the chicken to the skillet to coat the chicken in the glaze. Remove the chicken from the skillet and serve with the sauce on top.