This bread recipe uses fresh Boletus edulis because their soft texture blends better with the texture of the bread. Dried porcini become a little bit chewy upon reconstitution, so if you wish to substitute them, be sure to chop them up very small. Substitute about 1/4 cup dry porcini, reconstituted for an hour in 1 cup of water. Drain the water into another measuring cup, and top off to return to 1 cup, which you will then use for the bread.
Chop the mushrooms and briefly sear in a frying pan on medium heat, to kill any critters and partially cook. Knead all of the ingredients together, rise for 1 hour, form into a loaf, then rise again for 1 hour or more. Bake in a preheated oven at 350º for 1 hour. If you are using a bread machine, use the dough cycle and wait to put the mushrooms and olives in until after removing the kneaded dough (otherwise the machine will crush them too finely.) Fold the mushrooms and olives into the dough by hand, then form a loaf and let rise for an hour before cooking, as before. Feel free to substitute any mushroom you prefer. Agaricus work very well, among others. For a stronger olive flavor, use green olives instead of black.