In other words, he reversed the technique, which is to pan sear first and then finish off in the oven.
Cook's Illustrated Pan-Seared Chicken Breast Technique
(in my own words and with my own variations)
Boneless, skinless chicken breasts (about 6-8 oz. each), trimmed of excess fat
Kosher salt, 1/2 tsp. per breast
Cornstarch and watter slurry (whisk 1 tbs. cornstarch and enough water together to make a loose paste; increase if you have more than 4 chicken breasts)
2 tbs. butter, melted
1 tbs. flour
1 tsp. ground black pepper
Your favorite pan sauce or bottled sauce
Preheat oven to 275 degrees.
Place breasts on a piece of aluminum foil on a cookie tray or baking dish. The foil should be big enough to wrap over and full enclose the breasts (this is for easy clean up).
Poke each breast with a fork 5-6 times, and sprinkle each breast with 1/2 tsp of kosher salt. This will act like a mini-brine.
Cover the breasts with foil, so they are enclosed. Place on middle rack in the oven and bake 30-40 minutes, or until they're 145-150 degrees inside. (I cooked my chicken breasts 30 minutes).
Remove chicken from oven. Open foil and move chicken onto paper towels. Pat dry. Any juice that's in the foil can be used for a pan sauce if you're making one.
Heat a 12-inch skillet over medium-hight heat until hot. Add 1-2 tbs. of oil. Make slurry and brush 1/2 on the top of chicken breasts.
Place chicken, slurry side down, and brown for 3-4 minutes. While that side is browning, brush the remaining slurry on the other side.
Flip chicken with tongs when browned and brown the other side for 3-4 minutes, or until the chicken is 160 degrees internally.
Transfer chicken to a plate and let rest for 5 minutes. You can make a pan sauce now, use a prepared sauce, or serve as is.