In medium bowl, combine ricotta, egg, parmesan & salt - mix well until completely combined.
Add approximately ½ cup of flour to ricotta, and mix very lightly to just combine. The mixture should look like under mixed biscuit dough.
Turn the dough out on to a lightly floured work surface, and sprinkle the top of the dough with about 1 tablespoon of flour. Very lightly bring the dough together, sprinkling with another tablespoon of flour on to any spots where the dough still feels wet & sticky (see notes).
At this point I usually have ¼ cup of flour left.
Using a sharp knife, cut the dough into 2 roughly even portions (see notes).
Take one portion, and divide it roughly in half to make a quarter.
Lightly roll this quarter of dough in a long log - about 30 cm / 12 inches long and 2 cm / ¾ inches in diameter, then repeat for second quarter lightly sprinkling with flour as needed.
Repeat for remaining dough portion.
Dip the point of your sharp knife into the remaining flour, and cut gnocchi into 1 ½ cm / ⅗ inch pieces, re-flouring your knife point as you go.
If you are going to pan fry your gnocchi, place the butter into a non-stick fry pan over medium high heat.
Carefully place your gnocchi into boiling water (see note) - the gnocchi will rise to the surface when they are cooked, this should take around 2-3 mins (see notes).
Remove gnocchi from boiling water with a slotted spoon and allow them to drain slightly, before adding them to the hot-buttered fry pan & frying for 1 - 11/2 mins to colour slightly then adding them to a sauce of your choice, or add directly without frying (see notes).
Serve immediately.