Place chicken breasts between two sheets of plastic wrap, and use a rolling pin to flatten slightly. Coat each piece of meat in the Dijon mustard.
In three separate bowls, place flour, beaten egg and quinoa flakes. Dip each piece of meat in order: first in the flour, ensuring the chicken is completely coated, then in the egg, allowing any excess to drip away, and finally into the quinoa flakes.
Heat oil in a fry pan, or preheat your oven to 180 degrees Celsius. Pan fry each schnitzel until both sides are a golden brown. Alternatively, place each schnitzel on to a well-oiled baking tray and cook in the oven for approximately 20 minutes, or until brown.