Fry the bacon in a saucepan until golden brown. Leaving the fat in the pan, remove the bacon and set aside.
In the same pan, melt the butter in the bacon fat and sauté the onions until golden brown. Keeping the fat in the pan, remove the onions and set aside.
Add the bread to the pan and fry until lightly browned on all sides. Remove the bread from the pan, place in a mixing bowl and allow to cool.
In a separate bowl, stir together the milk, eggs and pepper. Pour over the bread and mix well. Let stand for at least 3 hours.
Combine the flour, bacon, onions and bread mixture and stir together to blend well. Dampen hands and form 8 dumplings from the mixture.
Bring salted water to a boil in a large pot. Carefully place dumplings in the boiling water and cook for 15 to 20 minutes.
Remove the dumplings from the water and drain. Arrange on a platter and sprinkle with the parsley.