Heat oil in a large saute pan, add the mushrooms and cook over medium heat for 12 minutes, allowing for the juices to cook out and the mushrooms to get soft. Remove them for the pan, add the onions to the same pan and cook , over medium heat until they are brown and sweet , about 15 minutes. It may be necessary to add a couple of tablespoons of water in the beginning of the cooking to get the onions to cook without burning. In a large bowl, beat the eggs until they loosen up. Add the cream and molasses, stir to incorporate. Add the mushrooms, onions, 3/4 cup of the cheese, and bread. Mix well to completely coat. Season highly with the salt and pepper. Let this mixture sit for 1 hour. Coat the inside of a 2 quart casserole dish with the butter. Dust with the bread crumbs. Preheat the oven to 325. After an hour, stir the mixture and pour into the prepared dish and sprinkle the top with the remaining cheese. Cover with foil and bake for 50 to 60 minutes.