Prepare the Chicken – Cut the chicken breasts in half lengthwise to create 4 total portions. Place a piece of plastic wrap on top and flatten to ½-inch thick. Repeat with remaining pieces. Evenly season both sides with salt and black pepper. Add the chicken to a baking dish or a large resealable plastic bag.
Marinate the Chicken – In a small bowl, combine ¼ cup of the pesto sauce and ¼ cup olive oil. Add it to the chicken and turn to coat. Cover and marinate in the refrigerator for 30 minutes or up to 24 hours.
Cook the Chicken – Heat a large skillet over medium heat, then add 2 tablespoons olive oil. Once hot and shimmering but not smoking, add the chicken. Use tongs to press down into the pan for maximum contact. Cook until golden brown, about 5 to 7 minutes. Flip and cook until the internal temperature reaches 160 to 165ºF (71 to 74ºC), about 5 to 7 minutes.
To Serve – Rest the chicken on a clean plate or cutting board for 5 minutes. Serve as whole pieces or slice them into strips. Serve with the remaining pesto sauce.
Notes
Storing: Store in an airtight container in the refrigerator for up to 5 days.
Reheating: Cover and microwave the chicken on high heat in 15 to 30-second increments until hot.
Cooking Chicken Thighs: Cook until the internal temperature reaches 165 to 170ºF (74 to 77ºC).