Preheat the oven to 400 degrees Fahrenheit. Spray a large casserole dish or baking sheet with cooking oil.
Remove the chicken from its packaging and place it on a large cutting board. Use paper towels to pat any excess moisture off of the chicken breasts. Use a sharp knife to slice each chicken breast through the center, creating four thin chicken breast filets. Skip this step if you’re using thin chicken cutlets or chicken tenders.
Crack the egg into a bowl and use a fork to whisk it vigorously until it is well-beaten.
Transfer the breadcrumbs, parmesan cheese (if adding), gluten free flour, garlic powder, sea salt, and black pepper to a large plate or a shallow bowl and stir everything together until the dry ingredients are combined.
Take one of the chicken filets in your hands and dip both sides of it into the beaten egg mixture. Move the egg coated chicken to the plate with the breading mixture and dip both sides into the mixture. You can use your hands to pile more of the breading on top of the chicken to create a thicker coat. Transfer the breaded chicken cutlet to the prepared baking dish and repeat for the remaining chicken pieces.
Bake chicken on the center rack of the preheated oven for 12 to 15 minutes, or until golden brown and the internal temperature reaches 165 degrees Fahrenheit. Insert a digital thermometer into the thickest part of the breast and wait until the numbers stop moving to get an accurate read. (See blog post above for skillet or air fryer instructions for alternate methods of cooking.)
Serve baked breaded chicken with your favorite side dishes such as rice pilaf, roasted vegetables, or salad for a balanced meal. If you love honey mustard chicken, blend the ingredients for the honey mustard sauce in a small blender (such as a Magic Bullet) until combined and use as a drizzle or dipping sauce.