For the dumplings: Whisk together the eggs and milk in a large bowl. Mix in the flour, chives and nutmeg. Set aside to rest until ready to use.
For the ham, cabbage and sauerkraut: Melt the butter in a large Dutch oven over medium-high heat. Add the onion and ham steak and cook until the onions begin to sweat, 5 to 6 minutes. Add the cabbage with the coriander, red pepper flakes and a large pinch of salt and cook until the cabbage begins to melt and break down, about 5 minutes. Stir in the beer, turkey stock and sauerkraut, bring to a simmer and cook for 30 minutes.
Bring large pot of salted water to boil. Spread the dumpling batter in a line down the back of a sheet tray or small cutting board. Dip a bench scraper in the boiling water, then use it to "cut" the dumplings into the pot, dipping the bench scraper in the boiling water in between each cut. Cook the dumplings until they begin to float to the surface, 2 to 3 minutes. Transfer the dumplings to the Dutch oven with the cabbage. Mix in the parsley and mustard and any additional salt and pepper if needed. Serve.