Dredge (or shake) chicken in flour and season with salt and pepper.
Melt butter in a large skillet over medium-high heat and brown chicken on both sides. Arrange browned chicken in a large baking dish in one layer.
In the same pan where chicken was browned, reduce fat to 2 tablespoons and reduce heat to medium. Add sliced mushrooms and cook slightly, 3-5 minutes. Add sour cream, white wine, and rosemary, and stir to combine.
Pour sour cream sauce over chicken, cover dish with foil and bake until chicken is cooked through, about 1 1/4 hour for bone-in chicken, 30-40 minutes for boneless chicken. Serve with rice or noodles. Enjoy!
