Cut one side of each Chicken Breast through the middle horizontally to within 1 cm of the other side, creating a pocket. Fill each Chicken Breast with Cheese mixture and close over the filling.
Coating:
Coat the outside of each Chicken Breast with Egg. Press Bread Crumb mixture over egg layer to coat each Chicken Breast. Arrange chicken breasts in a 23 cm x 33 cm baking dish.
Bake for about 45 minutes, until internal temperature is 75 ℃ / 165 ℉.
Pour Marinara Sauce over Chicken, top Cheese s. Bake 5 more minutes, (until Sauce is bubbling and Cheese is melted).