The utility that comes with the Template::Toolkit is called ttree. Before going farther I suggest reading this introduction to using the template toolkit for building websites.

Remember this. Templating tools are one of the most often re-invented wheels in the Perl world. We have quite a few of them, with very good ones suited to all sorts of different niches. Rather than roll your own I strongly recommend figuring out what your desired feature set is, and then go out and find one that already does that.