Preheat the Sous Vide Water Bath: Fill a large container or pot with water. Attach the sous vide precision cooker and set the temperature to 165°F (74°C).
Prepare the Chicken: Season chicken thighs with salt and pepper on a plate. Then place them to a zip-lock bag and arrange in a single layer.
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.)
Sous Vide Cook Chicken Thighs: Place the bag in the warm water bath and cook for 1 hour. (Make sure the chicken thighs are fully submerged while the seams of the bag are above water. You can add heavy kitchen items to weigh the bag down if necessary.)
Sear the Chicken: Remove the chicken from the bag and keep the juices. Pat dry the chicken with paper towels. (Make sure the surface is completely dry).
You can sear the chicken immediately by heating a skillet over medium-high heat, add oil and butter. When butter is completely melted, add the chicken thighs skin side down, cook for about 1 minute until the skin is nicely seared. Flip and cook the other side for 1 minute. (If you prefer to have a crispier skin, you can place the bag to an ice water bath and let the chicken cool for 15 minutes. Sear the skin side for about 5 minutes, and flip and sear the other side for 30 seconds. Remove from the pan.)
Make Honey Garlic Sauce: In the same pan, add garlic, honey, lemon juice, and soy sauce together with 2-3 spoons of the juices from the bag. Cook until the sauce thickens, about 4-6 minutes. (Taste the sauce, and more honey or soy sauce based on your preference.)
Add back the chicken in the skillet and drizzle the sauce over the chicken. Serve immediately! Garnish with finely chopped parsley if desired.