Place the soft ricotta cheese and Grana Padano or Parmigiano cheese in a large bowl and mix by folding the ingredients together. Add a small amount of flour (1/4 to 1/2 cup) to bind the dough and absorb the excess moisture.
Knead the dough on a lightly-floured work surface. It is important not to add too much flour because the gnocchi may get heavy.
Take a large piece of dough, and roll it out into thin logs, approximately 3/4-inch thick. Cut each log into 1/2-inch wide cubes. Make ridges on each gnocchi by using the back of a fork in a rolling action. The imprints will trap the sauce on the surface of the gnocchi. Continue until all the dough is used.
Place the gnocchi on a tray in a single layer underneath a cloth to prevent them from drying out. The gnocchi may be set in the refrigerator or freezer, until they're needed.
To cook the gnocchi: Add the gnocchi to a pot of boiling salted water for about a minute, or until they float to the surface.
The make the sauce: Melt the butter in a saucepan and add the fresh sage leaves. Drain the gnocchi and add them directly to the saucepan. Cook with the sauce about 30 seconds.