This is from "The Best of Ukrainian Cuisine". There must be a trick to making stuffed potato dumplings because when I made this, the filling kinda just disappeared inside them. It was pointless. The main mushroom effect was in the sauce. Cooking time includes mushroom soaking time. Perhaps it would work better if both the potatoes and mushroom filling were cooled to room temp (or colder) before filling them and then relying on the frying to heat them up (with the sauce going into the microwave for reheating).