For the curd dumplings, cream butter with lemon zest and salt. Stir in the eggs, pass in the curd cheese and mix in as well.
Cut the toast into small cubes and mix into the dumpling mixture together with the sour cream and flour. Let rest for about 20 minutes. Then form the dumplings.
Now bring salted water to a boil, put in the dumplings and cook for 12 to 15 minutes, depending on their size, until they rise.
Remove the dumplings from the water with a dumpling lifter and drain well. Slowly melt butter in a pan, lightly brown breadcrumbs in it on low heat and carefully roll dumplings in butter-crumb mixture.