Sauté 4 tbs. butter with the veal, chicken livers, mushrooms and sausages in a saucepan. Add a few tbs. of broth if the mixture is too dry. Cook for about 30 mins. Remove from heat and set aside.
Wash and clean the spinach, squeeze out excess water, chop and sauté with 2 tbs. butter for 5 mins. and set aside.
Combine meat and spinach mixtures together with 4 eggs, and salt and pepper. Grind finely using a food mill to make the stuffing smooth.
Take one sheet of dough and spread the stuffing, leaving an unfilled 1/2-in. border. Take the other sheet, place it on top and roll. Wrap with cheesecloth and cook floating in boiling, salted water. For this, use an oval pot or a pot that resembles a fish poacher, so that the ends of the cheesecloth can be tied to the handles of the pot. This way, the pasta roll will be floating and not sitting in the boiling water. Cooking time can be as long as 2 hours.
When cooked, take the roll out of the water, discard the cheesecloth, cut into 1/2-in. thick slices. Arrange them in a buttered baking dish, pour tomato sauce over, sprinkle with 2 tbs. Parmigiano, dot with butter and bake for 12 mins. at 375ºF.
Serves 6
