Take chicken breasts and pat them dry. Sprinkle salt, pepper, garlic powder, and paprika on both sides. Rub the seasoning gently so it sticks well. Let the chicken rest for ten minutes. This helps build strong flavor before cooking starts.

Heat olive oil in a large skillet over medium heat. Place chicken breasts in the pan carefully. Cook each side until golden brown. Do not cook fully yet. Remove chicken and place it in a baking dish for later baking.

In the same skillet, add butter. Toss in sliced onions and mushrooms. Cook until soft and slightly golden. Stir often to avoid burning. The vegetables should release a nice aroma. This step adds deep flavor to the smothered chicken sauce.

Pour chicken broth into the skillet with vegetables. Add heavy cream and stir slowly. Let it simmer for a few minutes until slightly thick. The sauce should look smooth and creamy. This becomes the rich topping for the chicken.

Place seared chicken into the baking dish. Pour the creamy mushroom and onion mixture over the chicken. Make sure each piece is fully covered. Sprinkle cheddar and mozzarella cheese evenly on top. This creates a cheesy, flavorful smothered layer.

Preheat oven to 375°F or 190°C. Bake chicken for 20–25 minutes. The cheese should melt completely and turn slightly golden. Chicken should be fully cooked and juicy. Remove carefully and let it rest before serving hot.