Place turkey between 2 sheets of heavy-duty plastic wrap, and flatten to 1/4-inch thickness, using a meat mallet or rolling pin. Sprinkle turkey with salt, pepper, and thyme. Dredge in flour.
Cook turkey breast slices in margarine and hot oil in a large skillet over medium heat 2 to 3 minutes on each side or until tender. Transfer turkey to a greased 13- x 9- x 2-inch baking dish. Place 1 slice of prosciutto on each turkey slice. Sprinkle evenly with cheeses. Pour broth into dish. Bake, uncovered, at 350° for 15 minutes or until bubbly. Serve immediately.