Cut the bread rolls into small cubes. Sprinkle 1/3 of them in a bowl with a little hot milk and soak.
Toast the remaining bread cubes in 2 tablespoons of hot butter until brown all over, only then stir in the chopped parsley – let cool.
Add the remaining softened butter with the eggs to the bread cubes, likewise add the toasted bread cubes. Mix everything, season with salt, pepper and mace and let it stand for about half an hour.
Shape the mixture into an oblong loaf and wrap it in a buttered napkin – butter only as much of the napkin’s working surface as is necessary to cover the dumpling.
Do not fold the tea towel in too tightly so that the dumpling has enough room to rise.
Place the roll on an insert in gently simmering water, of which it should be completely covered. Let it steep gently in an open saucepan for about 35 minutes, never boil it.
Unwrap the napkin dumpling, cut into 2-cm-thick slices and serve as a side dish.