如何通过twig-silex访问返回值

I'm new in silex and twig. I want to access a returned value from a function and put it in my twig template. This is my code :

namespace classes;

use Silex\Application;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
$blogPosts = array(
1 => array(
    'date'      => '2011-03-29',
    'author'    => 'igorw',
    'title'     => 'Using Silex',
    'body'      => '...',
),
);
class GlobalController
{
public function indexAction(Application $app, Request $request)
{

    $output = '';
    foreach ($blogPosts as $post) {
        $output .= $post['title'];
        $output .= '<br />';
    }

  return $output;
      }
    }

I want to access $output and show it in my template. Can I do that? because I have other similar functions and they are retrieving data from database and returning them as values, I want to include these values in the template .. Is that possible ?

I tried these but they didn't work :

{{ GlobalController.output }}
{# Or #}
{{ GlobalController.indexAction.output }}

Update : I added this in my routing:

$app->get('/news/', function () use ($app) {
return $app['twig']->render('news.php.twig', array(
'output' => $output,
));
});

and it gave me Undefined variable: output notice.

Thank you

When you're finishing up with your route, you need to show which twig template you're using and include all the variables that you want to use in twig:

return $app['twig']->render('some_template.twig', array(
    'output' => $output,
));

Now you can access the variable with {{ output }}