Bread used for containing soup
You don't need to worry about trying to bake hollow bread.

The typical way of doing this is to bake a stout, crusty French bread into a boule. You can use commercial yeast, but I recommend sourdough if you can.

Once baked, and cooled, you just cut a circular hole in the top of the boule and remove a big chunk. The larger the hole, the larger the portion of soup. If you were to actually hollow this out, you'd end up with a rather huge portion of soup. The finished product should end up looking exactly like those shown in this blog post.