With a mallet, pound chicken breasts thin. Cut into serving size pieces. Dip in flour. Dip in egg.
Melt 2 tablespoons butter or margarine and 1 tablespoon oil in a wide skillet. Saute chicken until light brown. Do not crowd pan, and add more oil if necessary to keep chicken from sticking. Place chicken on a serving platter, and keep in a warm oven.
Saute sliced mushrooms in oil and butter remaining in pan until released juices have evaporated and mushrooms begin to brown. Add chicken broth, Marsala wine, oregano, parsley, and meat extract. Stir well. Cook over high heat until liquid is reduced by half.
Remove pan from heat. Swirl in 2 tablespoons butter or margarine and lemon juice. Season with salt and pepper. Pour sauce over chicken, and sprinkle with cheese.