...
sub handler {
    my $r = shift;
    my $var = $r->dir_config('var');

    $ENV{'VAR'}      = $var;
    $ENV{'AM_I_SET'} = 'Yes';
    
    return Apache2::Const::OK;
}

##</code><code>##

my $r = shift;

# template initialization not shown
my $var = $r->dir_config('var');
$vars{'message'}  = "Var is: $var";
$vars{'message'} .= '<br />'.Dumper(\%ENV);

$template->process("hello.html", \%vars) || die $template->error();