- 4 skinless, boneless chicken breast halves
- 1/2 cup butter, melted
- 2 teaspoons ground mixed peppercorns
- 2 cups cooked white rice
- 1/2 (1 ounce) package dry onion soup mix, or to taste
- 1 1/2 cups water
- 1/2 onion, diced
- 1 (10.75 ounce) can condensed cream of chicken soup
- 1 cup sour cream
- 1/4 cup milk
- 1 teaspoon celery seed
- 1 teaspoon garlic powder
- 1 (6 ounce) package stuffing mix
- 1 cup hot water
- Preheat oven to 325 degrees F (165 degrees C).
- Coat chicken with melted butter in a 9×13-inch baking pan; sprinkle both sides of chicken with pepper.
- Spread cooked rice evenly into a separate 9×13-inch baking pan; sprinkle onion soup mix over rice. Pour 1 1/2 cups water over seasoned rice. Layer onion on rice where the chicken breasts will be placed.
- Mix cream of chicken soup, sour cream, milk, celery seed, and garlic powder in a bowl. Drop small spoonfuls of half the soup mixture onto rice; lightly spread mixture evenly over rice.
- Arrange chicken breasts, thickest parts toward the pan's edge, on the prepared onion sections atop the rice. Spoon remaining half of soup mixture over chicken.
- Mix stuffing mix and 1 cup hot water together in a bowl; spoon stuffing over chicken and rice. Cover pan tightly with aluminum foil.
- Bake in the preheated oven until chicken is no longer pink in the center and the juices run clear, about 1 hour. An instant-read thermometer inserted into the thickest piece should read at least 165 degrees F (74 degrees C).