Stir together 2 tablespoons butter and garlic. Loosen skin from turkey without detaching it; sprinkle salt and pepper under skin. Rub 2 tablespoons garlic mixture over meat. Place fruit slices, rosemary, and sage under skin; replace skin.
Rub remaining 1 tablespoon butter over skin; sprinkle with 1 teaspoon seasoned pepper. Place turkey breast on a lightly greased rack in a broiling pan. Add onion and chicken broth.
Bake at 350° for 1 hour and 30 minutes, basting every 30 minutes. Shield with foil, and bake 1 more hour or until a meat thermometer inserted into thickest breast portion registers 170°. Let stand 10 minutes before slicing. Serve with pan juices.