If you bake it, the best way to dry out bread, turn the oven on to about 300. Put the bread in on the rack, not on a cookie sheet, because you want the bread to dry out evenly. As soon as you put the bread in and close it up, turn off the oven and let it sit all night. This way, you don't have to watch it and don't use much energy. The closed oven will usually dry it out well. This is how I normally make bread crumbs for cooking. I will usually just put in a whole loaf on the rack, without overlapping the slices.