In a large mixing bowl, combine the flour and salt.
Make a well in the center and add the egg and water.
Mix until a dough forms. If the dough is too dry, add a little more water, a tablespoon at a time.
Knead the dough on a lightly floured surface for about 5-7 minutes, or until it is smooth and elastic.
Cover the dough with a damp cloth and let it rest for at least 30 minutes.
In a bowl, combine the finely chopped spinach, green onions, dill, parsley, and crumbled feta cheese (if using).
Season with salt and black pepper to taste.
Mix well to combine.
Divide the dough into small portions and roll each portion into a thin circle on a lightly floured surface.
Cut the dough into small squares, about 2 inches (5 cm) on each side.
Place a small spoonful of the filling in the center of each square.
Fold the dough over the filling to form a triangle or a half-moon shape, pressing the edges to seal tightly.
In a large pot, bring the vegetable or chicken broth to a boil.
Carefully add the dumplings to the boiling broth.
Cook the dumplings for about 5-7 minutes, or until they float to the surface and are cooked through.
Use a slotted spoon to remove the dumplings from the broth and transfer them to serving bowls.
Enjoy your meal!