1 1/2 cups all-purpose flour.
Rice either the pumpkin puree or the blue potatoes onto a sheet pan with a potato ricer. Make the pumpkin gnocchi and then the blue potato gnocchi.
Beat the egg with the salt and mix it into the pumpkin or blue potatoes with a fork.
Sprinkle the pumpkin or blue potatoes with 1 1/4 cup of the flour. For the pumpkin gnocchi only, add 1/8 tsp of grated nutmeg to the mixture. Gently knead to mix. The dough should be soft but not sticky. Add more flour if needed. (see notes) Cover and let the dough rest for 20 minutes.
Cut a piece of dough off with a bench knife, and roll it to form a long rope 1/2-inch in diameter.
Cut the rope into pieces 1-inch long.
Use a gnocchi roller or fork to give the gnocchi its classic shape. The gnocchi can also be cooked without being shaped.
To cook the gnocchi: Bring a pot of water to boil, add a tsp of salt to the boiling water. Drop the gnocchi into the boiling water. Cook in small batches (see notes).
When the gnocchi floats to the surface of the water, it is cooked. Use a slotted spoon to remove the gnocchi from the boiling water.
The gnocchi can be frozen on a sheet pan and then vacuum packed for storage for up to 6 months. Alternately, store the frozen gnocchi in a ziplock freezer bag for up to a month.
Make the pumpkin gnocchi separate from the blue potato gnocchi.