Begin by cutting your leftover bread rolls into 1/2 to 3/4 inch pieces, placing them in a large bowl.

Heat 1 cup of milk in a small saucepan until warm but not boiling. Pour the milk over the cut bread, press down gently and let sit for about 10–15 minutes.

While the bread is soaking, dice the onion. In a skillet, melt 2 tablespoons of butter and add the diced onion. Sauté for about 8–10 minutes until golden brown.

Combine the soaked bread mixture with the sautéed onions, chopped parsley, beaten eggs, crumbled bacon (if using), nutmeg, salt, and pepper. Knead in breadcrumbs until slightly sticky.

With floured hands, portion the mixture into 12 round balls. Place the formed Semmelknödel on a wooden board.

In a large pot, bring salted water to a gentle boil. Add the dumplings and let simmer for about 20 minutes.

For extra flavor, pan-fry the cooked dumplings in a skillet with butter until crispy and golden brown.