Cut each chicken breast into 3 large chunks or strips, or leave the breasts whole and pound them to an even thickness. Place the chicken in a bowl with 1 to 2 cups of milk or buttermilk, enough to cover it, and let it soak for 20 to 30 minutes, or overnight in the refrigerator. The soak is what tenderizes the meat.
Drain the milk completely and pat the chicken dry with paper towels. Wet chicken steams and dry chicken browns, so none of the marinade should follow the meat into the baking dish.
Preheat oven to 375 F. In a small bowl, combine the mayonnaise, 1/2 cup of the parmesan cheese and the seasonings.
Place the chicken in a 9x13 baking dish, spread the mixture evenly over the top, and sprinkle with the remaining parmesan. Bake uncovered, because a lid traps steam and softens the crust.
Bake 40 to 45 minutes if the breasts are whole, or 25 to 30 minutes for cut pieces, strips or cutlets, until the thickest part reaches 165 F. Cut pieces cook much faster than whole breasts, and baking them for the full 45 minutes is what makes the chicken dry. If the topping is still pale, finish it under the broiler for a minute or two.
Let it rest 5 minutes, then serve. A vegetable like steamed broccoli goes well alongside, with a dash of fresh parsley if you like.