Preheat oven to 250 degrees. Cut the bread into 1-inch cubes and place on a baking sheet in an even layer. Bake for 15 minutes, stirring once or twice. Let cool. Raise oven temperature to 350.
Melt 8 tablespoons butter in a large skillet over medium heat. Add the onion and cook until very soft, about 10 minutes. Add the garlic and cook for another 30 seconds. Add the mushrooms and cook until they have released their juices and the juices evaporate, about 15 minutes. Raise the heat, add the sherry, and cook until it has evaporated. Add the broth, and 1 teaspoon of both salt and pepper. Bring to a boil, reduce heat and simmer for 5 minutes.
Put the toasted bread cubes into a large bowl. Pour the broth and vegetables over and toss well. Add the parsley, dates, and cheese, mix well. Taste and add more salt and pepper if needed. Stir in the eggs.
Put the mixture into a greased baking dish, dot with the remaining butter, cover with foil, and bake for 30 minutes. Remove the foil and bake or another 30-40 minutes or until golden.
The cooled stuffing can also be cooked inside a turkey.