Cut the bread into small pieces and pour 1 cup of milk over them in a bowl. Saute the onion and garlic in oil until translucent, then add to the bread. Dice the leek greens and bacon, grate the raw potatoes, and add everything to the bowl. Stir in the buckwheat flour and salt. If the dough seems too dry, add a little milk. Cook a test dumpling in simmering salted water, and if it breaks, add a little more flour to the mixture.
Form 10 dumplings and simmer gently for 20 minutes, then serve.