Lay the chicken fillets flat on a sheet of cling film, sprinkle with salt and pepper, cover with another sheet of cling film and pound to a uniform thickness.
Place the pounded fillets between stacks of paper towels and press lightly to remove surface moisture.
Place the starch, beaten egg and panko in three shallow bowls.
Dredge each chicken thigh in starch; shake off the excess.
Dip each floured chicken thigh in the beaten egg, making sure that every inch of the surface is coated with egg.
Roll each chicken fillet in panko. Make sure that the panko coating is even.
Heat enough cooking oil so that it is at least two inches deep.
Over medium-high heat, fry the chicken fillets, flipping them after two minutes, until the breading is golden and crisp.