Preheat the oven to 400º.

Slice the chicken breasts horizontally to make two thinner chicken cutlets per breast.

Whisk the egg together with salt and pepper and then pour into a flat, shallow dish. Next, whisk together the breadcrumbs, Parmesan cheese, and garlic powder and pour into separate flat-bottomed container. Dip the chicken cutlets into the egg and then into the breadcrumbs so that they are well coated.

Spray a baking sheet (see link below in the notes) with cooking spray. Place each chicken cutlet on the baking sheet as you coat it with breadcrumbs.

Bake the chicken for 15 minutes, then flip each cutlet over and cook for another 10 minutes or until it reaches 165º in the center of the thickest part.

While the chicken bakes, prepare the spaghetti or zucchini noodles.

Heat spaghetti sauce in a saucepan on the stove or a dish in the microwave. When the chicken is done, remove the baking sheet from the oven. Spoon ¼ cup of hot spaghetti sauce over the chicken and then top with ¼ cup of shredded mozzarella.

Return the chicken to the hot oven for 3 minutes, until cheese is just melted. Turn the oven to broil and cook for 1 additional minute, to crisp the breadcrumbs and brown the cheese.

Serve one chicken cutlet with ½ cup of cooked spaghetti or zucchini noodles. Top noodles with spaghetti sauce and additional Parmesan cheese.