Bake the sliced pumpkinin the oven for about 40 minutes; remove the skin and purée with a fork. Add the grated Parmesan cheese and a pinch of salt. If it is very tender, add an egg. Place a sheet of pasta dough in a baking dish and set dollops of filling on it, well spaced apart. Cover the dough with the filling with another sheet of pasta dough, pressing around the dollops of filling with your fingers to seal the two sheets. Using a pastry wheel, cut the tortelli into squares. Boil them al dente, place in a dish and season with melted butter.