Don’t be afraid to improvise and experiment with a variety of fresh herbs and vegetables. If you’re a vegetarian, substitute vegetable stock for the chicken stock, then add tofu and your favorite vegetables.This pot pie is loaded with chunks of chicken breast, fresh vegetables, and creamy gravy, then topped with a flaky pastry crust. A velouté sauce is one of the sauces of French cuisine, that were designated the four "mother sauces" by Antonin Carême in the 19th century. The French chef Auguste Escoffier later classified tomato, mayonnaise, and Hollandaise the mother of all sauces as well.