For the porcini tortellini, soak dried porcini in water for 2 hours first, pour water away and soak mushrooms again for 2 hours, this time in soup.
Remove mushrooms from soup and save soup if necessary. Add salt and pepper to ricotta and finely mince mushrooms. Mix with the ricotta.
Prepare pasta dough according to basic recipe and cut out circles. Put a teaspoon of filling on each circle, brush the edge with beaten egg and fold the circle into a semicircle, then turn it into tortellini.
Cook tortellini briefly in boiling salted water. Melt butter. Serve tortellini with sage leaves and butter.