01 -
Pat chicken breasts dry using paper towels. Season both sides evenly with garlic powder, paprika, salt, and freshly ground black pepper.
02 -
Preheat a large oven-safe skillet over medium-high heat and add olive oil. Sear chicken breasts for 4 to 5 minutes per side until golden and just browned. Transfer chicken to a plate; chicken will finish cooking in oven.
03 -
Lower heat to medium. Melt butter in the same skillet, then add sliced onion and mushrooms. Sauté, stirring occasionally, for 8 to 10 minutes until onions are softened and golden, and mushrooms have released moisture. Vegetables should begin to caramelize.
04 -
Sprinkle flour evenly over onion and mushroom mixture. Stir to coat and cook for 1 minute to eliminate raw flour flavor. Gradually add chicken broth while whisking to form a smooth sauce free of lumps. Simmer for 2 to 3 minutes until gravy thickens.
05 -
Preheat oven to 375°F (190°C). Arrange seared chicken breasts in a baking dish. Spoon onion and mushroom mixture evenly over each piece. Drap a slice of cheese over each breast. Pour gravy over the top.
06 -
Cover baking dish tightly with foil. Bake for 20 to 25 minutes until chicken is fully cooked (internal temperature reaches 165°F), cheese is melted, and sauce is bubbling. Let rest for 3 minutes before serving.