Wash the fresh spinach thoroughly under cold running water to remove any sand. Drain by shaking it vigorously by hand or in a lettuce basket, then chop coarsely. If frozen spinach is used, thoroughly defrost and drain it. Bring 2 litre of chicken stock to a boil in a 3-4 quart saucepan and add the fresh or frozen chopped spinach. Simmer uncovered about 6 to 8 minutes, then pour the entire contents of the pan into a sieve set over a large bowl. Press down hard on the spinach with the back of a wooden spoon to extract all it's juices. Set the liquid aside in the bowl and chop the cooked spinach very fine. Melt 3 tablespoons of butter in the saucepan. When the foam subsides, remove the pan from the heat and stir in the flour. With a wire whisk, beat the hot stock into this white roux a little at a time. Return the saucepan to the heat and, stirring it constantly, bring it to the boil. Then add the spinach. Season soup with salt, pepper and nutmeg. Half cover the pan and simmer soup over low heat about 5 minutes longer. Stir occasionally. Garnish each serving of soup with a few slices of hard-cooked egg. On festive occasions, such as Easter, spinatsuppe is often served with a stuffed egg half floating in each soup bowl. To make these, remove the yolks from 2 or 3 hard-cooked eggs (depending on how many people you plan to serve) and mash them to a paste with about 1 to 2 teaspoons of softened butter. Roll the mixture into little balls and nestle 2 or 3 into each halved egg white.