Preheat your oven to 350 degrees Fahrenheit.
Spray your baking pan with cooking spray to prevent sticking.
In a bowl, combine the buttermilk and Dijon mustard.
Mix well, then place your chicken breasts in the mixture to marinate for at least 30 minutes.
In a separate bowl, mix flour, cornflakes, and all the herbs and spices.
Coat each marinated chicken breast with the cornflake mixture.
Arrange the coated chicken on the prepared baking pan.
Give them some space to ensure even cooking.
Bake in the oven for about 30 to 40 minutes.
Make sure the chicken reaches an internal temperature of 165 degrees Fahrenheit before serving.