Mushroom-filled gnocchi with butter and sage

I blend finely and add Philadelphia. I add Parmigiano.I add truffle salt if available and freshly ground pepper.I put the filling in a piping bag with a plain nozzle and set aside.I boil and rice the potatoes while hot and let cool slightly. I break the egg into the centre, add flour and mix quickly. The flour amount may vary with the potatoes. Do not overwork; the dough should not be sticky.The dough is ready.I cut pieces and roll into ropes thicker than ordinary gnocchi.I cut fairly large gnocchi.I stand them upright on the floured work surface and make a central hole with the floured handle of a wooden spoon.I pipe filling into each hole. I pinch the dough to close the hole. I roll and flour them into cylinders.I boil in salted water until they float, then leave a couple of minutes. I melt butter and sage in a large frying pan, add a few tablespoons of cooking water and the gnocchi, then mix quickly with a generous amount of Parmigiano.Serve immediately with butter and sage.