01 -
Turn the oven to 375°F and coat a baking dish lightly with oil.
02 -
Put the chicken breasts in the dish and sprinkle them with onion, garlic, salt, and pepper.
03 -
In a mixing bowl, combine the sour cream, mayo, ranch mix, mustard, lemon juice, and spices. Stir in the Parmesan at the end.
04 -
Spoon the sauce over the top of the chicken breasts, making sure they're well covered.
05 -
Bake for 25-30 minutes, or until the chicken's internal temp hits 165°F.