Cut the mushrooms into dice, and fry them for one minute in one tablespoonful of the butter. Beat the eggs, salt, pepper, and cream together, and put them in a saucepan. Add the butter and mushrooms to these ingredients. Stir over a moderate heat until the mixture begins to thicken. Take from the fire and beat rapidly until the eggs become quite thick and creamy. Have slices of toast on a hot dish. Heap the mixture on these, and garnish with points of toast. Serve immediately.