Cut the bread into narrow slices. In a saucepan, heat the milk until very warm, but do not bring to a boil. Moisten the bread slices with as much hot milk as the bread will absorb.
Wash the spinach well, blanch in salted water for a few minutes.
Strain in a sieve, squeeze well and chop or strain finely.
Melt the butter, sweat the crushed garlic clove and the finely chopped onion in it, add the chopped spinach and steam it for 5 minutes, let it cool down a bit.
Add the eggs and the spinach to the bread and mix. Season with salt, pepper and a pinch of nutmeg, add flour and breadcrumbs.
Dust the surface with flour. With wet hands, form small dumplings from the mixture and roll a little in flour.
Heat plenty of salted water. The dumplings will rise as they boil and need room to float. When the water boils bubbly, put the dumplings in and simmer quietly over low heat without a lid for about 15 minutes.
Melt 80 g of butter in a small pan. Drain the finished dumplings, sprinkle with freshly grated Parmesan and baste with melted butter, serve immediately.