Heat butter in a pan, add the diced speck and thinly sliced onion. Cook gently until golden and aromatic.
Place the cubed stale bread in a large bowl. Pour in the milk, the speck-onion mix, parsley, chives, egg, and black pepper.
Mix gently until a dough forms — avoid overmixing, which makes the dumplings dense.
With damp hands, shape into small balls of even size.
Drop into simmering broth and cook for 8–10 minutes, until firm and cooked through.
Serve hot in the broth.
