Cook pasta until tender, drain and transfer to a mixing bowl; add prosciutto and season to taste with salt and pepper. Drain the porcini through a cheesecloth lined sieve. Reserve liquid. Rinse grit from mushrooms and chop finely. In a skillet heat the butter and saute shallots until tender. Add mushrooms, chopped porcini and reserved liquid and cook until mushrooms are tender and have absorbed the liquid. Add heavy cream and bring to a boil; season to taste with salt and pepper. Toss with pasta and transfer to a buttered baking dish. Heat, covered until hot in a preheated 350 degree oven. Delicious with turkey, capon and ham.