Bake chicken fillets at 375 degrees Fahrenheit for 20 minutes, or until chicken is thoroughly cooked. Larger chicken fillets require more cooking time. There are several baking and seasoning recipes available, and choosing one is a matter of personal preference.
Season or marinate the chicken fillets in advance of baking. Lemon juice, salt, pepper and rosemary or thyme are all common seasonings. Lightly oil a baking tray, and place the chicken fillets in the pan. Bake for 20 to 30 minutes at 375 degrees Fahrenheit, or 350 degrees Fahrenheit if the oven has a fan. Use a meat thermometer to ensure that the center of the fillet is at least 165 F before eating. Cutting the chicken in half to ensure that it is not pink is another option. Other options include covering the chicken and baking for 1 hour at 350 F. Covering the chicken keeps the outside soft rather than crispy.
Some recipes call for stuffing the chicken with cream cheese or other fillings, but the cooking time is still 20 to 30 minutes. A popular recipe for roasted chicken fillets uses chicken marinated in olive oil, lemon juice, salt, pepper and rosemary baked in the oven at 375 degrees Fahrenheit for 20 to 30 minutes and then served over a vegetable dish, such as ratatouille.