Set sous vide machine to 60C/140F.
Season chicken breasts with salt to taste. Place chicken in freezer bag with olive oil, rosemary and thyme, and remove the air through a vacuum sealer or the displacement method. Drop the bag in the bath for an hour and a half.
Remove bag from bath. Take chicken out of the bag, pat dry and season with salt and pepper to taste. Set the bag containing the liquids to the side for the sauce.
Heat up small sauce pan on medium and add butter. Once butter is melted, add the liquids from the bag, including the rosemary and thyme, in to the pan. Bring liquid to a simmer, and cook for 1 minutes. Add flour to the sauce, and whisk constantly as the sauce begins to thicken. Once thick, remove from heat.
Heat up large skillet on medium high and add oil. Sear chicken breasts for 60 seconds on each side, or until browned. Remove from pan, and place on a plate to rest. Serve with herb butter sauce, and enjoy!