Put the breast in a dish. Any material works fine, but if you have a dish made in a refractory material, it's even better (cooking will be faster).
Sprinkle thyme, and add a drop of olive oil on top of the breast (optional).
Insert a probe in the middle of the breast, put the dish inside the oven, and set the oven to 80°C (180°F). (Do not pierce the breast more than once or meat will lose its juices while cooking, and be dry).The breast is ready when internal temperature reaches 68°C (154°F) - about 3h. Serve as is, with any type of vegetables, cream of broccoli, green peas with butter, steamed green beans with onions, mash cauliflower, cooked tomatoes....Or add some tomato sauce, or gravy, and serve with pasta. Good warm, or cold. Leftovers are versatile, minced in a salad, or reheated with vegetables.