Just like Perl, you can use single or double quotes:

#!/usr/bin/perl

use strict;
use Template;

my $template = Template->new();
$template->process( 
   \*DATA, { runme => sub { return "<$_[0]->{title}>" } } );
__DATA__
[% runme( title = "don't try this" ) %]
[download]

Produces:

<don't try this>
[download]

Chris
M-x auto-bs-mode