Place oysters shells on baking sheet pan. Heat saute pan, add olive oil and mushrooms and cook 2-3 minutes. Add chopped shallots and remove from pan. Add cream to pan, bring to a boil and reduce until thickened. Add mushrooms back into cream reduction. Season to taste. Place cream sauce over oysters and top with grated cheese. Bake in 400 degree preheated oven for 7-10 minutes. Remove and serve.