Pizza frittes are simply leftover pizza dough that my mother would break into little balls, fry, drain & shake up in a paper bag with some powdered sugar in the bottom.

I don't know if you are still reading this site, since your post was from 1997, but I think the other dish your grandmother made is gnocchi. My grandmother made it with Ricotta instead of potatoes & my mother once gave me the ratio of flour to eggs & ricotta - I don't know the potato version:

For every 1 lb. of ricotta, use 3 cups of flour and 3 eggs. Add a bit of water and some salt if desired.

The dough shouldn't be sticky. Break off a piece and roll it into a rope, about 2-inches in diameter. Cut into 1-2-inch pieces.

Press 2 fingers into the center of each piece and quickly roll toward you. The piece of dough should flip over and is now somewhat hollow inside.

Boil until they float.