In a small bowl combine milk and egg. Combine flour, crushed corn flakes, salt and pepper.
Flatten each chicken breast to about 1/4" thickness by pounding between sheets of waxed paper.
Dip Chicken into milk mixture, then into flour mixture, turning to coat.
In 10" skillet, melt 4 tbsp. butter. Add garlic and chicken. Cook over medium heat, turning occasionally, until golden brown (5 to 6 min.) Place chicken on serving platter; keep warm.
Add remaining 2 tbsp. butter to drippings in pan. Stir until butter melts; stir in lemon juice. Add green onions and mushrooms. Continue cooking, stirring occasionally, until heated through( 2 to 4 min). Spoon over chicken. Garnish with lemon slices and parsley.