4 tablespoons (1/2 stick) butter
Melt butter over medium heat.
Add mushrooms and shallots and sprinkle with salt and pepper.
Cook 10 minutes.
Add chicken and cook 10 minutes on each side, or until tender.
Transfer chicken to platter and sprinkle with grated cheese.
Top with mushroom mixture.
Cook and let stand 5 minutes or until cheese melts.