Step 1: Season the Chicken - Start by preheating your oven to 375 degrees and setting out a baking dish. In a large bowl, add your chicken breasts along with the salt, pepper, and onion powder. Take a moment to really coat each piece evenly. This is where the base flavor begins, so do not rush it. You want every bite to have that seasoned goodness.
Step 2: Sear the Chicken - Heat the vegetable oil in a large skillet over medium to high heat. Once the oil is hot, place the chicken in the pan. Let it sear for about three minutes on each side until it develops a golden brown crust. You are not cooking it through here, just building flavor. While that is happening, mix the sour cream and onion soup packet together in a small bowl until smooth and creamy.
Step 3: Build the Dish - Transfer the seared chicken into your prepared baking dish. Spoon the sour cream mixture over each piece, making sure they are well covered. This sauce is what makes the dish special, so do not be shy with it. Sprinkle the shredded cheddar cheese evenly over the top. It will melt down into the sauce and create a rich, comforting layer.
Step 4: Bake Until Tender - Cover the baking dish with foil and place it in the oven. Let it bake for 25 minutes. This allows the chicken to cook through gently while soaking up all that flavor. After that, remove the foil and return it to the oven for another five minutes. This step helps the cheese melt fully and gives the top a slightly golden finish.
Step 5: Finish and Serve - Once it comes out of the oven, let it rest for a couple of minutes. Sprinkle fresh parsley over the top if you like. When serving, spoon some of that extra sauce from the bottom of the dish over the chicken. Trust me, that is where all the flavor lives. Serve it over mashed potatoes or alongside your favorite sides and enjoy every bite.