Sauté the finely chopped onion in butter together with diced speck. Mix eggs and milk and pour over the cubed white bread. Add parsley and flour. Season with salt and pepper. Let the mixture rest for about 30 minutes. If it is too soft, add some breadcrumbs.
Form dumplings by hand using a spoon if needed. Simmer in boiling salted water for about 15 minutes. Sprinkle with chives and serve in meat or vegetable broth or as a side dish.