Pat the chicken breasts dry with paper towels. Season both sides with salt, pepper, paprika, and garlic powder. This helps the chicken develop a flavorful crust while cooking.

Heat olive oil in a large skillet over medium heat. Add the chicken and cook for five minutes per side. Remove the chicken when lightly golden and set it aside.

Add butter to the same skillet. Add sliced onions and cook for five minutes. Stir often until the onions become soft, golden, and fragrant. Add minced garlic during the final minute.

Sprinkle flour over the onions and stir well. Slowly pour in chicken broth while stirring. Cook for two minutes until the mixture begins to thicken.

Reduce the heat to low. Add sour cream, onion powder, and dried parsley. Stir gently until everything becomes smooth and creamy. Avoid boiling the sauce because sour cream can separate.

Place the seared chicken back into the skillet. Spoon some creamy sauce over each piece. Cover the skillet and cook for eight to ten minutes.

Sprinkle Parmesan cheese over the chicken and sauce. Cover again for two minutes. Let the cheese melt completely into the warm sauce for extra richness and flavor.

Check the thickest part of the chicken with a meat thermometer. Chicken should reach 165°F or 74°C internally. Remove the skillet from the heat once the chicken is fully cooked.

Sprinkle fresh parsley over the finished chicken. Let it rest for two minutes before serving. Spoon plenty of creamy onion sauce over each chicken breast.